A111413 a(n) = f(f(n+1))-f(f(n)), where f(m) = Euler(m) = A000111(m).

0, 0, 0, 15, 19391512129, 703237958001393736999896827714634659411015090272684227831001142371615151

Offset: 0

Author

N. J. A. Sloane, Nov 12 2005

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..6

Crossrefs

Cf. A000111.

Programs

Maple

b:= proc(u, o) option remember;
      `if`(u+o=0, 1, add(b(o-1+j, u-j), j=1..u))
    end:
a:= n-> (f-> f(f(n+1))-f(f(n)))(k-> b(k, 0)):
seq(a(n), n=0..5);  # Alois P. Heinz, Aug 17 2021

Mathematica

$RecursionLimit = Infinity;
t[n_, 0] := Boole[n == 0];
t[n_, k_] := t[n, k] = t[n, k-1] + t[n-1, n-k];
f[n_] := t[n, n];
a[n_] := f[f[n+1]] - f[f[n]];
Table[a[n], {n, 0, 5}] (* Jean-François Alcover, Apr 25 2022 *)

Extensions

Definition corrected by N. J. A. Sloane, Feb 14 2018