A256153 Primitive prime factors of the cyclotomic polynomial sequence Phi(5,k) in the order in which they occur.

5, 31, 11, 71, 311, 2801, 151, 61, 41, 271, 3221, 22621, 30941, 3761, 4931, 88741, 2711, 911, 251, 40841, 245411, 292561, 346201, 521, 8641, 4561, 637421, 732541, 837931, 17351, 601, 1801, 39451, 22571, 49831, 101, 4271, 194681, 191, 401, 2625641, 579281

Offset: 1

Author

Robert Price, Mar 16 2015

Keywords

• nonn

Comments

Phi(5,k) = k^4 + k^3 + k^2 + k + 1.

All terms end with the digit 1.

Links

• Robert Price, Table of n, a(n) for n = 1..1191

Crossrefs

Cf. A005529, A248874, A256144, A256145, A256146, A256148.

Programs

Mathematica

prim = {}; Do[prim = Join[prim, Complement[First /@ FactorInteger[Cyclotomic[5, k]], prim]], {k, 1000}]; prim

PARI

lista(nn) = {vs = []; for (n=1, nn, vp = factor(polcyclo(5,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