OFFSET
0,6
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..695
FORMULA
a(0) = 0, a(1) = a(2) = 1; a(n) = Sum_{k=0..n-3} binomial(n-3,k) * a(k).
MATHEMATICA
nmax = 31; A[_] = 0; Do[A[x_] = x + x^2 + x^3 A[x/(1 - x)]/(1 - x) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
a[0] = 0; a[1] = a[2] = 1; a[n_] := a[n] = Sum[Binomial[n - 3, k] a[k], {k, 0, n - 3}]; Table[a[n], {n, 0, 31}]
PROG
(SageMath)
@CachedFunction
def a(n): # a = A346050
if (n<3): return (0, 1, 1)[n]
else: return sum(binomial(n-3, k)*a(k) for k in range(n-2))
[a(n) for n in range(51)] # G. C. Greubel, Nov 28 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Jul 02 2021
STATUS
approved