OFFSET
1,2
COMMENTS
sigma(n, k) is the sum of the k-th powers of the divisors of n.
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 1..35
FORMULA
log(a(n)) ~ n*(n+1)*log(n)/2. - Vaclav Kotesovec, Aug 21 2019
EXAMPLE
a(4) = sigma(4,1)*sigma(4,2)*sigma(4,3)*sigma(4,4) = 7*21*73*273 = 2929563.
MAPLE
with(NumberTheory): seq(product(sigma[k](n), k = 1..n), n = 1..10); # Vaclav Kotesovec, Aug 20 2019
MATHEMATICA
Table[Times@@DivisorSigma[Range[n], n], {n, 10}] (* Harvey P. Dale, Oct 21 2017 *)
PROG
(PARI) vector(12, n, prod(k=1, n, sigma(n, k)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Colin Barker, Jan 22 2014
STATUS
approved