A082083 a(n)=A082081[n! ]=A082081[A000142[n]] Fixed points of iterated A008475 function initiated at factorials as initial values.

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

Links

Table of n, a(n) for n=1..50.

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}]

Crossrefs

Cf. A001414, A056239, A008475, A082081-A082084, A000961, A000142.

Sequence in context: A336190 A238159 A080156 * A287558 A024917 A081402

Adjacent sequences: A082080 A082081 A082082 * A082084 A082085 A082086

Keyword

nonn

Author

Labos Elemer, Apr 08 2003

Status

approved