A389717 a(n) = Sum_{k=0..floor(4*n/11)} binomial(k,4*n-11*k).

1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 5, 1, 0, 15, 1, 0, 35, 1, 1, 70, 1, 9, 126, 1, 45, 210, 1, 165, 330, 2, 495, 495, 14, 1287, 715, 92, 3003, 1001, 456, 6435, 1366, 1821, 12870, 1837, 6189, 24310, 2533, 18565, 43758, 4029, 50389, 75583, 8721, 125971, 125991, 25194

Offset

0,15

Links

Seiichi Manyama, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0,0,4,0,0,-6,0,0,4,0,1,-1).

Formula

G.f.: (1-x^3)^3 / ((1-x^3)^4 - x^11).

a(n) = 4*a(n-3) - 6*a(n-6) + 4*a(n-9) + a(n-11) - a(n-12).

Prog

(PARI) my(N=60, x='x+O('x^N)); Vec((1-x^3)^3/((1-x^3)^4-x^11))

Crossrefs

Cf. A389718, A391265, A392272.

Sequence in context: A200420 A176324 A081817 * A361550 A123260 A019113

Adjacent sequences: A389714 A389715 A389716 * A389718 A389719 A389720

Keyword

nonn,easy

Author

Seiichi Manyama, Jan 08 2026

Status

approved