login
A364591
G.f. satisfies A(x) = 1/(1-x) + x^4*A(x)^4.
3
1, 1, 1, 1, 2, 5, 11, 21, 40, 85, 197, 457, 1028, 2289, 5193, 12069, 28338, 66445, 155563, 365701, 865815, 2061133, 4919431, 11758741, 28165412, 67657225, 162977081, 393445865, 951438682, 2304494349, 5591221729, 13588455861, 33075115578, 80616857525, 196742749155
OFFSET
0,5
FORMULA
a(n) = Sum_{k=0..floor(n/4)} binomial(n-k,3*k) * binomial(4*k,k) / (3*k+1).
PROG
(PARI) a(n) = sum(k=0, n\4, binomial(n-k, 3*k)*binomial(4*k, k)/(3*k+1));
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Jul 29 2023
STATUS
approved