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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.
1
0, 3, 15, 138, 1720, 27180, 522984
OFFSET
1,2
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.
FORMULA
a(n) = n^n - A163950(n).
CROSSREFS
Sequence in context: A113379 A267018 A262911 * A005816 A179470 A270524
KEYWORD
more,nonn
AUTHOR
Carlos Alves, Aug 06 2009
STATUS
approved