# Guess the number sequence #1

Find out the next number in the sequence.

2 - 6 - 39916800 - 6227020800 - 355687428096000 - ?

2! - 3! - 11! - 13! - 17! - ?

which means that I'd guess the next number would be

19! = 121,645,100,408,832,000....

What I don't understand is if this is the case,

5! = 120 and 7! = 5040 are missing from the sequence.

It is therefore otherwise that

we have 2! - 3! (skip 5!, skip 7!) - 11! - 13! - 17! (skip 19!, skip 23!, skip 29!) - 31! (The patter is that we take factorials of the first two primes, then skip the next two, then take the factorials of the first three primes, then skip the next three, etc.)

In which case the answer is

31! = 8,222,838,654,177,922,817,725,562,880,000,000

• I was thinking of Rot13(snpgbevnyf), the first time I saw this riddle, but you got there first :) – Mr Pie Jul 27 '18 at 12:36
• Thanks @user477343! I'd be interested to see how the meta-puzzle (without the rot13(snpgbevnyf) ) unfolds, I'm not sure which of the two options I presented is most correct (if either haha)! – El-Guest Jul 27 '18 at 12:37
• I am really surprised you figured the correct answer (31!) out! Are you some sort of master in this? D: – Quotenbanane Jul 27 '18 at 12:39
• I think I just really like your puzzles ;) we seem to be on the same wavelength with your asking and my answering these past two days! – El-Guest Jul 27 '18 at 13:04