A082088 a(n) is the fixed point if function A008472[=sum of prime factors with no repetition] is iterated when started at initial value prime[n]!.

2, 5, 7, 17, 3, 41, 31, 5, 7, 5, 7, 197, 2, 281, 43, 7, 5, 5, 73, 2, 7, 7, 13, 5, 7, 5, 3, 7, 13, 3, 7, 7, 7, 7, 571, 7, 7, 5, 7, 7, 5, 7, 5, 7, 2, 7, 19, 3, 3, 67, 5, 2, 71, 43, 7, 71, 239, 7, 7, 7699, 2, 5, 313, 8893, 2, 3, 199, 5, 5, 2, 5, 2, 3, 7, 6361, 3, 97, 5, 19, 97, 7, 2593, 5, 5

Offset

1,1

Links

Table of n, a(n) for n=1..84.

Formula

a(n)=A082087[A000142(p[n])].

Example

n=100,p(100)=541,start at 541! and get iteration list=
{541!,24133} ended immediately in a(100)=24133;
n=99,p(99)-523,start at 523! and get a list of
{523!,23592,988,34,19}, a(99)=19.

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, Prime[w]! ], {w, 2, 100}]

Crossrefs

Cf. A008472, A034387, A007504, A075860, A082087.

Sequence in context: A067580 A325210 A181447 * A075881 A208241 A089727

Adjacent sequences: A082085 A082086 A082087 * A082089 A082090 A082091

Keyword

nonn

Author

Labos Elemer, Apr 09 2003

Status

approved