A082084 - OEIS

%I #7 Oct 15 2013 22:31:54

%S 0,2,5,5,5,19,5,7,7,11,13,13,23,13,19,101,61,5,19,5,11,5,5,7,23,7,5,7,

%T 283,293,5,5,7,367,379,389,23,7,463,5,13,11,29,5,23,7,7,19,5,5,5,5,61,

%U 7,73,47,857,7,947,5,29,7,13,5,5,19,137,7,5,7,11,23,353,53,11,1471,1489

%N a(n)=A029908[n! ]=A029908[A000142[n]] Fixed points of iterated A001414 function if started at factorials as initial values.

%e Fixed point seems to be always a prime:tested for 1<n<201

%e n=20!=2432902008176640000: a(20)=5 with fixed-point-list=

%e {2432902008176640000,154,20,9,6,5,5}

%t ffi[x_] := Flatten[FactorInteger[x]] lf[x_] := Length[FactorInteger[x]] ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}] ep[x_] := Table[Part[ffi[x], 2*w], {w, 1, lf[x]}] slog[x_] := Apply[Plus, ba[x]*ep[x]] Table[FixedPoint[slog, w! ], {w, 1, 128}]

%Y Cf. A001414, A056239, A008475, A082081-A082083, A000961, A000142.

%K nonn

%O 1,2

%A _Labos Elemer_, Apr 08 2003