A082084 a(n)=A029908[n! ]=A029908[A000142[n]] Fixed points of iterated A001414 function if started at factorials as initial values.

0, 2, 5, 5, 5, 19, 5, 7, 7, 11, 13, 13, 23, 13, 19, 101, 61, 5, 19, 5, 11, 5, 5, 7, 23, 7, 5, 7, 283, 293, 5, 5, 7, 367, 379, 389, 23, 7, 463, 5, 13, 11, 29, 5, 23, 7, 7, 19, 5, 5, 5, 5, 61, 7, 73, 47, 857, 7, 947, 5, 29, 7, 13, 5, 5, 19, 137, 7, 5, 7, 11, 23, 353, 53, 11, 1471, 1489

Offset

1,2

Links

Table of n, a(n) for n=1..77.

Example

Fixed point seems to be always a prime:tested for 1<n<201
n=20!=2432902008176640000: a(20)=5 with fixed-point-list=
{2432902008176640000,154,20,9,6,5,5}

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]}] slog[x_] := Apply[Plus, ba[x]*ep[x]] Table[FixedPoint[slog, w! ], {w, 1, 128}]

Crossrefs

Cf. A001414, A056239, A008475, A082081-A082083, A000961, A000142.

Sequence in context: A256302 A205396 A082086 * A094236 A340777 A205444

Adjacent sequences: A082081 A082082 A082083 * A082085 A082086 A082087

Keyword

nonn

Author

Labos Elemer, Apr 08 2003

Status

approved