OFFSET
0,4
LINKS
Index entries for linear recurrences with constant coefficients, signature (7,-21,36,-35,21,-7,1).
FORMULA
a(n) = A369814(7*n).
a(n) = Sum_{k=0..floor(n/3)} binomial(n+4*k,n-3*k).
a(n) = 7*a(n-1) - 21*a(n-2) + 36*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7).
G.f.: 1/(1 - x - x^3/(1 - x)^6).
PROG
(PARI) a(n) = sum(k=0, n\3, binomial(n+4*k, n-3*k));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Jun 22 2024
STATUS
approved