A256144 Primitive prime factors of the cyclotomic polynomial sequence Phi(9,k) in the order in which they occur.

3, 73, 757, 19, 829, 2467, 37, 1063, 262657, 333667, 1772893, 80749, 1609669, 397, 18973, 541, 21061, 109, 1270657, 991, 34327, 523, 29989, 64008001, 85775383, 127, 297613, 7792003, 2017, 4987, 5167, 308933353, 433, 8209, 444979, 14437, 41203, 729027001

Offset: 1

Author

Robert Price, Mar 16 2015

Keywords

• nonn

Comments

Phi(9,k) = k^6 + k^3 + 1.

Links

• Robert Price, Table of n, a(n) for n = 1..1521

Crossrefs

Cf. A005529, A248874.

Programs

Mathematica

prim = {}; Do[prim = Join[prim, Complement[First /@ FactorInteger[Cyclotomic[9, k]], prim]], {k, 1000}]; prim

PARI

lista(nn) = {vs = []; for (n=1, nn, vp = factor(polcyclo(9,n))[,1]; for (i=1, #vp, if (!vecsearch(vs, vp[i]), print1(vp[i], ", "); vs = vecsort(concat(vs, vp[i]),,8););););} \\ Michel Marcus, Mar 20 2015