OFFSET
0,9
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..3000
Index entries for linear recurrences with constant coefficients, signature (8,-28,56,-70,56,-28,8).
FORMULA
G.f.: (1 - x)^7/((1 - x)^8 - x^8).
a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) for n > 7.
MATHEMATICA
a[n_] := Sum[Binomial[n, 8*k], {k, 0, Floor[n/8]}]; Array[a, 37, 0] (* Amiram Eldar, May 25 2021 *)
PROG
(PARI) {a(n) = sum(k=0, n\8, binomial(n, 8*k))}
(PARI) N=66; x='x+O('x^N); Vec((1-x)^7/((1-x)^8-x^8))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Mar 14 2019
STATUS
approved