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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!. 5
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, 7, 7, 7, 7, 7, 7, 197, 197, 197, 197, 2, 2, 281, 281, 281, 281, 43, 43, 43, 43, 43, 43, 7, 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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..85.

FORMULA

a(n) = A075860(A000142(n)).

EXAMPLE

n=73: iteration list=

{73!=61234458376886086861524070385274672740778091784697328983823014963978384987221689274204160000000000000000,639,74,39,16,2,2}

MATHEMATICA

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}]

CROSSREFS

Cf. A007504, A008472, A034387, A075860.

Sequence in context: A245083 A233565 A121359 * A263317 A256300 A023850

Adjacent sequences:  A082084 A082085 A082086 * A082088 A082089 A082090

KEYWORD

nonn

AUTHOR

Labos Elemer, Apr 09 2003

STATUS

approved

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Last modified December 8 18:37 EST 2019. Contains 329865 sequences. (Running on oeis4.)