OFFSET
1,4
FORMULA
G.f.: Sum_{k>=1} k^4 * x^(k^2) / (1 - x^k).
MATHEMATICA
Table[DivisorSum[n, #^4 &, # <= Sqrt[n] &], {n, 1, 65}]
nmax = 65; CoefficientList[Series[Sum[k^4 x^(k^2)/(1 - x^k), {k, 1, nmax}], {x, 0, nmax}], x] // Rest
PROG
(PARI) A347143(n) = { my(s=0); fordiv(n, d, if((d^2)>n, return(s)); s += (d^4)); (s); }; \\ Antti Karttunen, Aug 19 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Aug 19 2021
STATUS
approved