A281794 The largest prime factor of (1+n^2)*(1+n^3).

1, 2, 5, 7, 17, 13, 37, 43, 19, 73, 101, 61, 29, 157, 197, 211, 257, 29, 307, 181, 401, 421, 463, 53, 577, 601, 677, 73, 757, 421, 67, 37, 331, 151, 1123, 613, 1297, 137, 67, 1483, 1601, 547, 1723, 139, 631, 1013, 109, 103, 461, 1201, 61, 2551, 541, 919

Offset: 0

Author

R. J. Mathar, Jan 30 2017

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A006530, A014442, A081256, A281661.

Programs

Magma

[#f eq 0 select 1 else f[ #f][1] where f is Factorization((1+n^2)*(1+n^3)): n in [0..60]]; // Vincenzo Librandi, Jun 03 2017

Maple

A281794 := proc(n)
    A006530((1+n^2)*(1+n^3)) ;
end proc:
seq(A281794(n),n=0..60) ;

Mathematica

Table[Max[Transpose[FactorInteger[(1 + n^2) (1 + n^3)]][[1]]], {n, 0, 60}] (* Vincenzo Librandi, Jun 03 2017 *)

PARI

a(n) = if (n==0, 1, my(f=factor((1+n^2)*(1+n^3))); vecmax(f[, 1])); \\ Michel Marcus, Jun 03 2017; corrected Jun 13 2022

Formula

a(n) = max( A014442(n), A081256(n)).

a(n) = A006530(A281661(n)).