OFFSET
0,2
FORMULA
a(n) = 1 + Sum_{k=0..n-1} a(floor(k/4)) * a(n-1-k).
PROG
(PARI) a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=1+sum(j=0, i-1, v[j\4+1]*v[i-j])); v;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Nov 28 2023
STATUS
approved