A082086 - OEIS

A082086

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

2, 5, 5, 5, 13, 23, 61, 19, 5, 283, 5, 23, 13, 29, 7, 61, 947, 29, 137, 11, 353, 23, 199, 5, 47, 2381, 5, 103, 359, 13, 5, 5, 7, 5, 47, 19, 577, 7, 5, 29, 5, 5, 5, 41, 11, 23, 239, 7, 11, 5, 11, 5, 23, 11821, 31, 5, 5, 13669, 7, 193, 5, 991, 89, 7, 13, 18199, 131, 113, 20849

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..69.

FORMULA

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

EXAMPLE

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

MATHEMATICA

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

CROSSREFS