A063744 a(n) = sigma(a(n-1)) * number of divisors of a(n-1), a(1)=2.

2, 6, 48, 1240, 46080, 10537956, 4755179520, 21601740363840, 320026934857728000, 5141450783421628416000, 254900463912224253775282176, 22582740409889438693597632266240

Offset

1,1

Links

Harry J. Smith, Table of n, a(n) for n = 1..40

Mathematica

NestList[DivisorSigma[1, #]DivisorSigma[0, #]&, 2, 15] (* Harvey P. Dale, Aug 09 2021 *)

Prog

(PARI) s(n) = if(n<2, n=2, sigma(s(n-1))*numdiv(s(n-1))); for(n=1, 20, print(s(n)))
(PARI) { for (n=1, 40, if (n>1, a=sigma(a)*numdiv(a), a=2); write("b063744.txt", n, " ", a) ) } \\ Harry J. Smith, Aug 29 2009

Crossrefs

Sequence in context: A003053 A113296 A275462 * A141609 A096313 A346788

Adjacent sequences: A063741 A063742 A063743 * A063745 A063746 A063747

Keyword

easy,nonn

Author

Jason Earls, Aug 14 2001

Status

approved