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A248874 Primitive prime factors of the cyclotomic polynomial sequence Phi(10,k) in the order in which they occur. 6
11, 61, 5, 41, 521, 101, 191, 331, 1181, 9091, 13421, 19141, 2411, 71, 31, 1531, 61681, 9041, 2251, 152381, 185641, 224071, 211, 5791, 9161, 431, 1021, 271, 53951, 401, 71261, 21821, 251, 4051, 1151041, 259631, 132631, 241, 6781, 1824841, 2031671, 41011 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Phi(10,k) = k^4 - k^3 + k^2 - k + 1.

Note that except for a(3), all terms end with the digit 1.

LINKS

Robert Price, Table of n, a(n) for n = 1..1218

MATHEMATICA

prim = {}; Do[prim = Join[prim, Complement[First /@ FactorInteger[Cyclotomic[10, k]], prim]], {k, 1000}]; prim

CROSSREFS

Cf. A005529.

Sequence in context: A055826 A324622 A156704 * A073625 A307628 A106993

Adjacent sequences:  A248871 A248872 A248873 * A248875 A248876 A248877

KEYWORD

nonn

AUTHOR

Robert Price, Mar 14 2015

STATUS

approved

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Last modified December 11 02:13 EST 2019. Contains 329910 sequences. (Running on oeis4.)