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A082083
a(n)=A082081[n! ]=A082081[A000142[n]] Fixed points of iterated A008475 function initiated at factorials as initial values.
5
0, 2, 5, 11, 16, 7, 37, 149, 7, 27, 11, 11, 23, 2389, 49, 11, 31, 19, 67, 109, 13, 8, 25, 8, 461, 179, 1319, 9, 193, 16, 7, 4931, 121, 7, 9, 8, 7, 8, 2895630887, 25, 19, 13, 19, 41, 2209493509721, 32, 5939, 23, 43, 11
OFFSET
1,2
EXAMPLE
Fixed point is always a prime or a true power of prime:
a term from A000961.
n=20!=2432902008176640000, a(20)=109 because
fixed point list={2432902008176640000,269439,214,109}}
MATHEMATICA
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]}] sex[x_] := Apply[Plus, ba[x]^ep[x]] Table[FixedPoint[sex, w! ], {w, 1, 128}]
KEYWORD
nonn
AUTHOR
Labos Elemer, Apr 08 2003
STATUS
approved