OFFSET
0,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
FORMULA
E.g.f.: (Sum_{k>=0} prime(k+1)*x^k/k!)^3. - Ilya Gutkovskiy, Mar 10 2018
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):
seq(a(n), n=0..30); # Alois P. Heinz, Mar 10 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];
Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Jun 05 2018, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved