A138902 a(n) = d!, where d is the number of digits in n.

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 6, 6

Offset: 0

Author

Odimar Fabeny, May 16 2008

Keywords

• easy
• nonn
• base

Links

• James Spahlinger, Table of n, a(n) for n = 0..10000

Crossrefs

Different from A047726. Cf. A138908.

Programs

Haskell

a138902 = a000142 . a055642 -- James Spahlinger, Oct 09 2012

Mathematica

a[n_]:=IntegerLength[n]!;Array[a,103,0] (* James C. McMahon, Jun 24 2025 *)

Formula

a(n) = A000142(A055642(n)). - James Spahlinger, Oct 09 2012

Extensions

Edited by N. J. A. Sloane, Sep 29 2011, at the suggestion of Franklin T. Adams-Watters