OFFSET
0,8
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
FORMULA
G.f. A(x) satisfies: A(x) = 1 + x + x^2 + x^3 + x^4 + x^5 * A(x) * (A(x) - 1).
MATHEMATICA
a[0] = a[1] = a[2] = a[3] = a[4] = 1; a[n_] := a[n] = Sum[a[k] a[n - k - 5], {k, 1, n - 5}]; Table[a[n], {n, 0, 48}]
nmax = 48; A[_] = 0; Do[A[x_] = 1 + x + x^2 + x^3 + x^4 + x^5 A[x] (A[x] - 1) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
PROG
(SageMath)
@CachedFunction
def a(n): # a = A346049
if (n<5): return 1
else: return sum(a(k)*a(n-k-5) for k in range(1, n-4))
[a(n) for n in range(51)] # G. C. Greubel, Nov 28 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Jul 02 2021
STATUS
approved