|
|
A236329
|
|
a(n) = sigma(n,1) * sigma(n,2) * ... * sigma(n,n).
|
|
3
|
|
|
1, 15, 1120, 2929563, 38464354656, 80529415686720000, 538252697895729090560000, 1045011472134222568417452736171875, 14983270528936392555878952946810076508388237, 30023920804570215919584229032152609459437167079578240000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
sigma(n, k) is the sum of the k-th powers of the divisors of n.
|
|
LINKS
|
|
|
FORMULA
|
|
|
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
|
|
|
STATUS
|
approved
|
|
|
|