OFFSET
0,3
FORMULA
G.f.: (1-x^2-x^3)/((1-x^2-x^3)^2 - 4*x^5)^(3/2).
D-finite with recurrence 2*n*(2*n+1)*a(n) +3*(n-1)*(2*n-3)*a(n-1) +4*(-2*n^2-3*n+4)*a(n-2) +2*(-10*n^2+n+27)*a(n-3) +2*(-4*n^2+11*n+27)*a(n-4) +(-2*n^2-27*n-27)*a(n-5) +2*(-4*n^2+7*n+18)*a(n-6) +3*(2*n+3)*(n-1)*a(n-7)=0. - R. J. Mathar, Oct 17 2024
PROG
(PARI) a(n) = sum(k=0, n\2, (k+1)*binomial(k, n-2*k)^2);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 17 2024
STATUS
approved