OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..452
FORMULA
a(0) = 1; a(n) = Sum_{k=0..n-1} binomial(n+4*k-1,n-k-1) * a(k).
MATHEMATICA
nmax = 21; A[_] = 0; Do[A[x_] = 1 + x A[x/(1 - x)^5]/(1 - x) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
a[0] = 1; a[n_] := a[n] = Sum[Binomial[n + 4 k - 1, n - k - 1] a[k], {k, 0, n - 1}]; Table[a[n], {n, 0, 21}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Feb 20 2022
STATUS
approved