login
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
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
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
KEYWORD
nonn
AUTHOR
Robert Price, Mar 14 2015
STATUS
approved