A081256 Greatest prime factor of n^3 + 1.

2, 3, 7, 13, 7, 31, 43, 19, 73, 13, 37, 19, 157, 61, 211, 241, 13, 307, 7, 127, 421, 463, 13, 79, 601, 31, 37, 757, 271, 67, 19, 331, 151, 1123, 397, 97, 43, 67, 1483, 223, 547, 1723, 139, 631, 283, 109, 103, 61, 181, 43, 2551, 379, 919, 409, 2971, 79, 103, 3307, 163

Offset

1,1

Comments

Record values appear to match the terms of A002383 for n>1. - Bill McEachen, Oct 18 2023

Links

R. J. Mathar and T. D. Noe, Table of n, a(n) for n = 1..10000 (first 5000 terms from R. J. Mathar)

Formula

a(n) = A006530(A001093(n)). - M. F. Hasler, Jun 13 2018

Maple

A081256 := proc(n)
    A006530(n^3+1) ;
end proc:
seq(A081256(n), n=1..20) ; # R. J. Mathar, Feb 13 2014

Mathematica

Table[Max[Transpose[FactorInteger[n^3 + 1]][[1]]], {n, 25}]

Prog

(PARI) a(n)=my(f=factor(n^3+1)); f[#f~, 1] \\ Charles R Greathouse IV, Mar 08 2017
(PARI) A081256(n)=vecmax(factor(n^3+1)[, 1]) \\ It seems slightly slower to get the last element using ...[-1..-1][1]. - M. F. Hasler, Jun 15 2018

Crossrefs

Cf. A081257, A081258, A096173, A096174.

Cf. A006530, A001093, A002383.

Sequence in context: A329413 A225093 A278007 * A084955 A273056 A026472

Adjacent sequences: A081253 A081254 A081255 * A081257 A081258 A081259

Keyword

easy,nonn

Author

Jan Fricke, Mar 14 2003

Extensions

More terms from Harvey P. Dale, Mar 22 2003

More terms from Hugo Pfoertner, Jun 20 2004

Status

approved