OFFSET
0,8
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..3000
Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-2).
FORMULA
G.f.: (1 - x)^5/((1 - x)^6 + x^6).
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - 2*a(n-6) for n > 5.
MATHEMATICA
a[n_] := Sum[(-1)^k * Binomial[n, 6*k], {k, 0, Floor[n/6]}]; Array[a, 37, 0] (* Amiram Eldar, May 25 2021 *)
PROG
(PARI) {a(n) = sum(k=0, n\6, (-1)^k*binomial(n, 6*k))}
(PARI) N=66; x='x+O('x^N); Vec((1-x)^5/((1-x)^6+x^6))
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Seiichi Manyama, Mar 21 2019
STATUS
approved