OFFSET
0,8
COMMENTS
This sequence is different from A005708.
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..5000
FORMULA
a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/6)} a(k) * a(n-1-6*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)\6, v[j+1]*v[i-6*j])); v;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Dec 01 2023
STATUS
approved