OFFSET
1,2
EXAMPLE
a(5) = 1^5 + (1^4 +2^4) + (1^3 +3^3) + (1^2 +2^2 +4^2) + (1^1 +5^1) = 1 + 17 + 28 + 21 + 6 = 73.
MAPLE
with(numtheory): s:=proc(n, k) local div: div:=divisors(n): sum(div[j]^k, j=1..tau(n)) end: a:=n->sum(s(i, n-i+1), i=1..n): seq(a(n), n=1..25); # Emeric Deutsch, Jul 13 2005
PROG
(PARI) a(n) = sum(k=1, n, sigma(k, n-k+1)); \\ Michel Marcus, Aug 16 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Jul 07 2005
EXTENSIONS
More terms from Emeric Deutsch, Jul 13 2005
STATUS
approved