OFFSET
0,2
COMMENTS
Self-convolution of A001316.
FORMULA
G.f. A(x) satisfies: A(x) = (1 + 2*x)^2 * A(x^2). - Ilya Gutkovskiy, Jul 09 2019
MATHEMATICA
nmax = 50; CoefficientList[Series[Product[(1 + 2 x^(2^k))^2, {k, 0, Floor[Log[2, nmax]] + 1}], {x, 0, nmax}], x]
a[n_] := a[n] = Sum[2^(DigitCount[k, 2, 1] + DigitCount[n - k, 2, 1]), {k, 0, n}]; Table[a[n], {n, 0, 50}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Jul 04 2019
STATUS
approved