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 A256153 Primitive prime factors of the cyclotomic polynomial sequence Phi(5,k) in the order in which they occur. 1
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 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 MATHEMATICA prim = {}; Do[prim = Join[prim, Complement[First /@ FactorInteger[Cyclotomic[5, k]], prim]], {k, 1000}]; prim PROG (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 CROSSREFS Cf. A005529, A248874, A256144, A256145, A256146, A256148. Sequence in context: A297472 A299129 A255677 * A238196 A352347 A172030 Adjacent sequences: A256150 A256151 A256152 * A256154 A256155 A256156 KEYWORD nonn AUTHOR Robert Price, Mar 16 2015 STATUS approved

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Last modified December 9 04:08 EST 2023. Contains 367681 sequences. (Running on oeis4.)