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%I #6 Aug 17 2017 06:01:08
%S 0,3,15,138,1720,27180,522984
%N 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.
%C 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.
%F a(n) = n^n - A163950(n).
%Y Cf. A163947, A163950.
%K more,nonn
%O 1,2
%A _Carlos Alves_, Aug 06 2009