OFFSET
0,2
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..1000
FORMULA
a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-1} a(floor(k/5)) * a(n-1-k).
MATHEMATICA
terms = 30; A[_] = 0; Do[A[x_] = 1/(1-x-x*(1+x+x^2+x^3+x^4)*A[x^5])+ O[x]^terms // Normal, terms]; CoefficientList[A[x], x] (* Stefano Spezia, Nov 16 2025 *)
PROG
(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=v[i]+sum(j=0, i-1, v[j\5+1]*v[i-j])); v;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Nov 26 2023
STATUS
approved