A163949 The number of functions in a finite set that are not obtainable by a composition power of any other function. Similar to A163947, but it excludes self compositions.

0, 3, 15, 138, 1720, 27180, 522984

Offset: 1

Author

Carlos Alves, Aug 06 2009

Keywords

• more
• nonn

Comments

It is similar to A163947, but the difference is expressed by the nontrivial sequence: 0, 3, 9, 54, 320, 1590, 6552... excluding solutions by powers of the function itself.

Crossrefs

Cf. A163947, A163950.

Formula

a(n) = n^n - A163950(n).