OFFSET
0,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
MAPLE
b:= proc(n, k) option remember; `if`(k=1, ithprime(n+1), add(
b(j, floor(k/2))*b(n-j, ceil(k/2))*binomial(n, j), j=0..n))
end:
a:= n-> b(n, 3)/2:
seq(a(n), n=0..30); # Alois P. Heinz, Jun 07 2018
MATHEMATICA
b[n_, k_] := b[n, k] = If[k==1, Prime[n+1], Sum[b[j, Floor[k/2]] b[n-j, Ceiling[k/2]] Binomial[n, j], {j, 0, n}]];
a[n_] := b[n, 3]/2;
a /@ Range[0, 30] (* Jean-François Alcover, Nov 16 2020, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved