OFFSET
0,5
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..1000
FORMULA
a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/3)} binomial(n-2*k,k) * a(n-1-3*k).
PROG
(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, (i-1)\3, binomial(i-2*j, j)*v[i-3*j])); v;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Feb 25 2023
STATUS
approved