1, 2, 6, 42, 1806, ?
What is the next number in the series? The answer to the puzzle is as below.
3,263,442
How to get it:
1, 1*(1+1), 2(2+1), 6(6+1), 42(42+1), 1806(1806+1) = 1, 2, 6 , 42, 1806, 3263442,…
The pattern is each number multiplied by the next number, and then do the same for the answer.
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March 4th, 2009 at 10:09 am
thank you so much. i m very happy to see this solution. if i dont see this, i can only solve in infinity
March 13th, 2009 at 8:51 pm
Hy,
today my Mathteacher asked us a question how to do this:P
In 4 minutes I came on the solution !
But I said to him ” That´s pretty simple:1×1+1=2,2×2+2=6,6×6+6…”
I was the only in my class who came on this way ^^
March 18th, 2009 at 12:21 pm
Thanks for the solution (I really didn’t get it).
Kind regards
Greetings from Zurich/Switzerland. Visit our country!
March 23rd, 2009 at 8:18 pm
There is a second solution:
3270666
1 1*2(2 is the next prime ) 2*3(3 is the next prime) 6*7(7 is the next prime)…
March 23rd, 2009 at 8:51 pm
Phil’s answer is the same answer…
n * (n+1) = (n*n) + n
NO DIFERENCE !!!
POLO from Buenos Aires - Argentina
++
March 25th, 2009 at 9:06 am
Why does it begin with 1?
To my opinion it should start with 0!
0=0*(0+1)
March 27th, 2009 at 9:47 pm
Hi together from Germany!
My colleague found the solution on the web, that’s why I am looking for what he found 
I got it from my colleague this afternoon… -nice thing on a Friday afternoon
@ Phil: 4 minutes??? Oh my… -What did you need all the time for? How’s this: 1 minute! (No kidding and not showing off!)
…And I am not “in training” anymore… out of school for more than 20 years already
Take care!
Linda
March 29th, 2009 at 10:04 am
1 2 6 42 1806 3263442
March 29th, 2009 at 10:05 am
because 1 2 (2×3) (6×7) (42×43) (1806×1807)
April 1st, 2009 at 8:05 pm
i only found 2940042
12/(1+1)=6
126/(2+1)=42
12642/(6+1)=1806
126421806/(42+1)=2940042
Strange
April 4th, 2009 at 2:43 pm
1-2(2×3)(6×7)(42×43)(1806×1807)=3263442
April 14th, 2009 at 7:46 pm
They say, you need an IQ of 120 or higher to solve this… I needed about one minute solve it. Temptation to look it up on the internet was strong, but I did it only afterwards.:-)
April 15th, 2009 at 8:43 pm
m=1
m*(m+1) т.е. 1*(1+1)=2; 2*(2+1)=6 и тд
или
(m^2)+m т.е. 1^2+1=2; 2^2+2=6; 6^2+6=42; 42^2+42=1807
April 20th, 2009 at 2:13 pm
Sebi apparently only took one minute to solve this.
We’ll I can beat that, because it only took me a total of a few seconds (to type it into Google and find the answer).
Yeah I’m lazy - or stupid.
Possibly both.
April 21st, 2009 at 6:27 pm
see the trend…1×1=1
1×2=2
2×3=6
6×7=42
42×43=1806
1806×1807=3263442
answer= each result times 1 plus itself gives you the next number…
April 22nd, 2009 at 12:44 am
er…Daniel your alternate solution is wrong.
You seem to forget that 5 is a prime number as well.
following your solution the series should have been:
1,2,6,30,210,2310,30030….and so on…
no idea how you came up with 3270666.
April 22nd, 2009 at 8:51 am
Necromorph,
Daniel meant a prime next to the previous row member.
April 22nd, 2009 at 8:57 am
Next prime number:
Next to the last number. 5 less than six, so 7 is
correct.
U
April 23rd, 2009 at 5:48 pm
Darn it…everybody is googling the answers..I was pointed here by a friend who said he solved it in 30 secs…:) by googling it.
Without any help..took me less than 10 seconds to get the answer..only to find out everyone is googling it ..heheh
April 27th, 2009 at 9:30 pm
Im 14 years old, i got the solution x*2x x ie 1×1+1, 2×2+2 etc,
but the an a leveller maths student got X+1 x X, which also works. which is it?
April 29th, 2009 at 3:26 pm
FOR STU - you’r not the only one to google it :)))))))) fast and easy :)))))))))
April 30th, 2009 at 8:07 am
Allmighty Google! 10sec! :-)))
May 4th, 2009 at 4:27 pm
1×1=1=+1=2
2×2=4=2=6
6×6=36=6=42×42=1764=42=1806
1806×18096=3261636=1806=3263442
May 5th, 2009 at 6:02 am
1×1=1=+1=2
2×2=4=2=6
6×6=36=6=42×42=1764=42=1806
1806×18096=3261636=1806=3263442
…
holy mother of god. You need some math lessons. because you just said that 1=2 and 4 = 2 = 6. (they seem to be different numbers to me lol)
May 6th, 2009 at 11:52 am
i did it in 20 seconds (without google!). it took me 5 more to calculate the final number - i was on the phone at that moment.
May 7th, 2009 at 10:02 pm
#
DCDude Says:
April 23rd, 2009 at 5:48 pm
Darn it…everybody is googling the answers..I was pointed here by a friend who said he solved it in 30 secs…:) by googling it.
Without any help..took me less than 10 seconds to get the answer..only to find out everyone is googling it ..heheh
—> fucking lier. cant read the text in 10 secs. i solved it in 20 sec+ 15-30sec while i typed it in to the calculator.
May 8th, 2009 at 1:51 pm
Hi guys,
got it by email, solved in less than a minute.
I guess I was lucky.
Got the same approach than Phil ;o)
BTW, no google but the calculator for the last one !
Lazy boy…
Sometime, Sudoku at level 1 are more difficult than level 3.
Why so ???
I got it fast this time but might be stuck to simplier one next time (ok, this one wasn’t so so difficult ;o)
Have a nice week-end to all !
May 8th, 2009 at 3:35 pm
You are all virgins. get a life
May 10th, 2009 at 2:31 am
Whp Cares, all I want is next weeks Lotto Numbers::::
May 11th, 2009 at 8:48 am
hey, did you now that people which find this sokution have à IQ higher than 120 ?
May 12th, 2009 at 4:57 am
Googling it doesn’t solve the maths problem, it only solves the problem of where to locate an answer that you hope is right. Of course if you have not had the pleasure of solving it mathematically yourself, you can never really be confident of the answer spoon fed to you by Google
May 12th, 2009 at 9:13 pm
If you add 1 to each number you get Sylvester’s sequence, see http://en.wikipedia.org/wiki/Sylvester’s_sequence. The sum of the inverse of each number is one.
1 = 1/2 + 1/3 + 1/7 + 1/43 + 1/1807 + …
In mathematics this is called the greedy Egyptian version of 1. See the website for an explanation.
May 15th, 2009 at 3:42 pm
LOL @ Stu…being “smart” or “intelligent” doesnt mean you know all the answers, just where to find them!!
i did the same thing, i tried it for a little then said screw it and looked it up. so who’s to say.
May 18th, 2009 at 7:48 am
ben, there’s no evidence that IQ has any bearing on the ability to solve number sequence puzzles. Some people are very capable in that department and utterly useless in others - and vice versa. It’s not about ‘intelligence’, it’s about the ability to recognize patterns and logical groups.
I find it hysterical that people here feel the need to brag about how quickly they solved the puzzle, though, which is why I will refrain from doing so. Wow, you’re all a pack of genii. Now get off the computer and attempt some realistic social interaction that does not involve you telling the other person how brilliant you think you are. It’s very unbecoming.
May 20th, 2009 at 12:12 am
Dont get the first 1.. Help
:-S
May 26th, 2009 at 8:50 am
TRYING TO FIND RESULTS FOR IQ TEST. FIND THE 6th NUMBER IN SEQUENCE EG. 1,2,6,42,1806 ?????
May 28th, 2009 at 1:37 pm
I may have missed it, but none of the above answers (obtained via thinking or by means of googling around)actually provides the means to generate the COMPLETE series in question from scratch (1, 2, 6, 42, 1806…). There is no way to justify including “1″, the first term, if one follows any of the answers posted above.
There is a simple math expression that does generate the complete series, inlcluding its first term. The best thing about it is that it does not appear to have been posted anywhere where Goggle can find it. Drop me a line, ands I’ll be happy to share it.
May 29th, 2009 at 8:56 pm
Hello!
I found another right solution!
This is the way I solve it:
- You group all the previous number
- You divide by the number that comes twice before
- You multiply by the previous number
Starting with 1,2, you have:
12*1/2 = 6
Next step: 1,2,6
126*2/6 = 42
Next step:1,2,6,42
12642*6/42=1806
And I get obviously another result for the next number:
126421806*42/1806 = 2940042
May 31st, 2009 at 12:05 pm
i’m 16, did this in approx. 5 mins…
so fuck youse 
now to really prove something; i have an active social life & i’m not a virgin!!
June 1st, 2009 at 4:17 pm
It was too easy! Solution is:
1×1=1=+1=2
2×2=4=2=6
6×6=36=6=42×42=1764=42=1806
1806×18096=3261636=1806=3263442
But I think this question is not enough to test our IQ level
June 8th, 2009 at 9:03 pm
mates im 12 and it only took me 4 min 2 work out so i dont no y your googleing it. its sad 2 try trick your mates by sayin u can work it when all u did was dos it make u fell hapy when u lie to your mates
July 1st, 2009 at 8:07 pm
I agree with Utku’s solution and the answer I got was
4,263,442. Each number was multiplied by the next number up in sequence.
June age 79,
July 2nd, 2009 at 1:39 pm
Hey guys,
They say that it takes a quantity surveyor 30 secs to figure out, an engineer 1 hour, and a doctor 6 hours.
I dont know if thats true or not, but I got around 1 minute using logic as opposed to maths, but basic mathematical knowledge is required.
August 21st, 2009 at 8:44 pm
I am 7 and i solve it in 90 seconds.
September 21st, 2009 at 1:35 am
all those who googled it are the real smart people out there the rest of you are merely lucky or working with calculators, in any case the real leaders don’t reinvent the wheel, they research and think out side the box….
Well done googlers!