OFFSET
1,2
FORMULA
MATHEMATICA
nmax = 55; CoefficientList[Series[Sum[x^(2^k) /(1 - x^(2^k))^3, {k, 0, Floor[Log[2, nmax]] + 1}], {x, 0, nmax}], x] // Rest
a[n_] := If[EvenQ[n], a[n/2] + n (n + 1)/2, n (n + 1)/2]; Table[a[n], {n, 1, 55}]
Table[(1/2) DivisorSum[n, Boole[IntegerQ[Log[2, n/#]]] # (# + 1) &], {n, 1, 55}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Oct 08 2020
STATUS
approved