A309702 G.f. A(x) satisfies: A(x) = A(x^2) / (1 - x - x^2 - x^3).

1, 1, 3, 5, 12, 20, 42, 74, 148, 264, 506, 918, 1730, 3154, 5876, 10760, 19938, 36574, 67536, 124048, 228664, 420248, 773878, 1422790, 2618646, 4815314, 8859904, 16293864, 29974958, 55128726, 101408308, 186511992, 343068964, 630989264, 1160606794, 2134665022

Offset

0,3

Links

Table of n, a(n) for n=0..35.

Formula

G.f.: Product_{k>=0} 1/(1 - x^(2^k) - x^(2^(k+1)) - x^(3*2^k)).

Mathematica

nmax = 35; A[_] = 1; Do[A[x_] = A[x^2]/(1 - x - x^2 - x^3) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
nmax = 35; CoefficientList[Series[Product[1/(1 - x^(2^k) - x^(2^(k + 1)) - x^(3 2^k)), {k, 0, Floor[Log[2, nmax]] + 1}], {x, 0, nmax}], x]

Crossrefs

Cf. A000073, A018819, A173285, A309703.

Sequence in context: A266819 A245939 A089292 * A358369 A143360 A234005

Adjacent sequences: A309699 A309700 A309701 * A309703 A309704 A309705

Keyword

nonn

Author

Ilya Gutkovskiy, Aug 13 2019

Status

approved