A024692 a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = floor((n+1)/2), s = A023533.

1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A023533.

Programs

Magma

A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
[(&+[A023533(k)*A023533(n-k+1): k in [1..Floor((n+1)/2)]]): n in [1..100]]; // G. C. Greubel, Jul 14 2022

Mathematica

A023533[n_]:= A023533[n]= If[Binomial[Floor[Surd[6*n-1, 3]] +2, 3] != n, 0, 1];
A024692[n_]:= A024692[n]= Sum[A023533[k]*A023533[n+1-k], {k, Floor[(n+1)/2]}];
Table[A024692[n], {n,100}] (* G. C. Greubel, Jul 14 2022 *)

SageMath

def A023533(n):
    if binomial( floor( (6*n-1)^(1/3) ) +2, 3) != n: return 0
    else: return 1
[sum(A023533(k)*A023533(n-k+1) for k in (1..((n+1)//2))) for n in (1..100)] # G. C. Greubel, Jul 14 2022

Formula

a(n) = Sum_{k=1..floor((n+1)/2)} A023533(k)*A023533(n-k+1).