cp's OEIS Frontend

A082087 a(n) is the fixed point if function A008472 (= sum of prime factors with no repetition) is iterated when started at initial value n!.

%I A082087 #9 Sep 04 2017 21:26:43
%S A082087 2,5,5,7,7,17,17,17,17,3,3,41,41,41,41,31,31,5,5,5,5,7,7,7,7,7,7,5,5,
%T A082087 7,7,7,7,7,7,197,197,197,197,2,2,281,281,281,281,43,43,43,43,43,43,7,
%U A082087 7,7,7,7,7,5,5,5,5,5,5,5,5,73,73,73,73,2,2,7,7,7,7,7,7,7,7,7,7,13,13,13,13
%N A082087 a(n) is the fixed point if function A008472 (= sum of prime factors with no repetition) is iterated when started at initial value n!.
%F A082087 a(n) = A075860(A000142(n)).
%e A082087 n=73: iteration list=
%e A082087 {73!=61234458376886086861524070385274672740778091784697328983823014963978384987221689274204160000000000000000,639,74,39,16,2,2}
%t A082087 ffi[x_] := Flatten[FactorInteger[x]] lf[x_] := Length[FactorInteger[x]] ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}] sopf[x_] := Apply[Plus, ba[x]] Table[FixedPoint[sopf, w! ], {w, 2, 100}]
%Y A082087 Cf. A007504, A008472, A034387, A075860.
%K A082087 nonn
%O A082087 1,1
%A A082087 _Labos Elemer_, Apr 09 2003