A191624 Largest prime factor of n^n - n^(n-1) - n^(n-2) - ... - n^2 - n - 1.

7, 19, 293, 1493, 179, 1091, 10593529, 379721, 165664841, 66987982331, 240717199, 28048051, 133933781, 25506609089573701, 107140256350247, 793435901761, 268232479553269300213, 4075297, 3063504618316968426599, 1372263056872621, 7514001866134191512025247

Offset

3,1

Links

Daniel Suteu and Harvey P. Dale, Table of n, a(n) for n = 3..72 (terms 3..52 from Harvey P. Dale)

Formula

a(n) = A006530(A191690(n)).

Maple

A006530 := proc(n) max ( numtheory[factorset](n) ) ; end proc:
A191690 := proc(n) n^n-add( n^j, j=0..n-1) ; end proc:
A191624 := proc(n) A006530(A191690(n)) ; end proc:
seq(A191624(n), n=3..15) ; # R. J. Mathar, Jun 23 2011

Mathematica

Table[With[{s=n^Range[0, n]}, FactorInteger[Last[s]-Total[Most[s]]][[-1, 1]]], {n, 3, 20}] (* Harvey P. Dale, Feb 02 2015 *)

Prog

(PARI) a(n) = if(n==0, return(1)); vecmax(factor(n^n - (n^n-1)/(n-1))[, 1]); \\ Daniel Suteu, Jun 09 2022

Crossrefs

Cf. A006530, A191690.

Sequence in context: A201479 A228150 A331404 * A221740 A364572 A335990

Adjacent sequences: A191621 A191622 A191623 * A191625 A191626 A191627

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jun 12 2011

Extensions

More terms from Harvey P. Dale, Feb 02 2015

Status

approved