OFFSET
0,11
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..3506
Index entries for linear recurrences with constant coefficients, signature (9,-36,84,-126,126,-84,36,-9,1,1).
FORMULA
G.f.: (1-x)^8/((1-x)^9 - x^10).
a(n) = 9*a(n-1) - 36*a(n-2) + 84*a(n-3) - 126*a(n-4) + 126*a(n-5) - 84*a(n-6) + 36*a(n-7) - 9*a(n-8) + a(n-9) + a(n-10) for n > 9.
a(n) = A017877(9*n).
MATHEMATICA
a[n_] := Sum[Binomial[k, 9*(n-k)], {k, 0, n}]; Array[a, 38, 0] (* Amiram Eldar, Jun 21 2021 *)
PROG
(PARI) {a(n) = sum(k=0, n, binomial(k, 9*(n-k)))}
(PARI) N=66; x='x+O('x^N); Vec((1-x)^8/((1-x)^9-x^10))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Mar 07 2019
STATUS
approved