OFFSET
1,2
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 1..760
Eric Weisstein's World of Mathematics, Divisor Function
FORMULA
G.f.: g(g(x)), where g(x) = Sum_{k>=1} x^k/(1 - x^k) is the g.f. of A000005.
MATHEMATICA
g[x_] := g[x] = Sum[x^k/(1 - x^k), {k, 1, 30}]; a[n_] := a[n] = SeriesCoefficient[g[g[x]], {x, 0, n}]; Table[a[n], {n, 30}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Apr 01 2019
STATUS
approved