%I #17 Aug 23 2024 22:04:03

%S 2,5,5,5,13,23,61,19,5,283,5,23,13,29,7,61,947,29,137,11,353,23,199,5,

%T 47,2381,5,103,359,13,5,5,7,5,47,19,577,7,5,29,5,5,5,41,11,23,239,7,

%U 11,5,11,5,23,11821,31,5,5,13669,7,193,5,991,89,7,13,18199,131,113,20849

%N Fixed points when A001414 is iterated and started at factorials of prime numbers.

%F a(n) = A029908(A000142(A000040(n))) = A029908(prime(n)!).

%e n=100, prime(100) = 541, start at 541!, the list is: {541!,...,46374,195,21,10,7} so a(100)=7.

%t sopfr[n_] := Total[Times @@@ FactorInteger[n]]; a[n_] := FixedPoint[sopfr, Prime[n]!]; Array[a, 100] (* _Jean-François Alcover_, May 06 2017 *)

%Y Cf. A008475, A082081, A000142, A000040, A000961.

%K nonn

%O 1,1

%A _Labos Elemer_, Apr 08 2003