OFFSET
1,2
COMMENTS
LINKS
FORMULA
G.f.: Sum_{i>=0} x^(2^i)/(1 - x^(2^i)) / Product_{j>=0} (1 - x^(2^j)).
EXAMPLE
a(4) = 10 because we have [4], [2, 2], [2, 1, 1], [1, 1, 1, 1] and 1 + 2 + 3 + 4 = 10.
MAPLE
b:= proc(n, i) option remember; `if`(n=0, [1, 0], `if`(i<0, 0, (p->
`if`(p>n, 0, (h-> h+[0, h[1]])(b(n-p, i))))(2^i)+b(n, i-1)))
end:
a:= n-> b(n, ilog2(n))[2]:
seq(a(n), n=1..56); # Alois P. Heinz, May 04 2021
MATHEMATICA
Rest[CoefficientList[Series[Sum[x^2^i/(1 - x^2^i), {i, 0, 20}]/Product[1 - x^2^j, {j, 0, 20}], {x, 0, 56}], x]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Jan 27 2017
STATUS
approved