OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (7,-15,20,-15,6,-1).
FORMULA
a(n) = A005708(6*n).
a(n) = Sum_{k=0..n} binomial(n+5*k,n-k).
a(n) = 7*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6).
G.f.: 1/(1 - x - x/(1 - x)^5).
PROG
(PARI) a(n) = sum(k=0, n, binomial(n+5*k, n-k));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Jun 22 2024
STATUS
approved