A309026 Expansion of x * Product_{k>=0} (1 + x^(2^k) + x^(2^(k+4))).

0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 3, 2, 2, 1, 3, 2, 2, 1, 3, 2, 2, 1, 3, 2, 2, 1, 4, 2, 2, 1, 4, 2, 2, 1, 4, 2, 2, 1, 4, 2, 2, 1, 5, 3, 3, 2, 4, 2, 2, 1, 5, 3, 3, 2, 4, 2, 2, 1, 6, 3, 4, 2, 4, 2, 2, 1, 6, 3, 4, 2, 4, 2, 2, 1, 7, 4, 4, 2

Offset

0,18

Links

Table of n, a(n) for n=0..100.

Formula

a(n) = 0 for n <= 0, a(1) = 1; a(2*n) = a(n), a(2*n+1) = a(n-7) + a(n+1).

Mathematica

nmax = 100; CoefficientList[Series[x Product[(1 + x^(2^k) + x^(2^(k + 4))), {k, 0, Floor[Log[2, nmax]] + 1}], {x, 0, nmax}], x]

Crossrefs

Cf. A002487, A112970, A309025.

Sequence in context: A160987 A230773 A338732 * A160986 A287867 A023126

Adjacent sequences: A309023 A309024 A309025 * A309027 A309028 A309029

Keyword

nonn

Author

Ilya Gutkovskiy, Jul 07 2019

Status

approved