S000370


Numbers n such that 5^n+1 has only one primitive prime factor.

0, 1, 2, 3, 4, 5, 6, 9, 12, 14, 24, 28, 44, 45, 46, 54, 55, 58, 60, 67, 99, 101, 103, 118, 124, 144, 192, 210, 229, 250, 265, 268, 310, 347, 399, 496, 532, 567, 615, 835, 1047, 1081, 1258, 1494, 1944, 2050, 2313, 2397, 2498, 2728, 3324, 3418, 3646, 3862

1

S000370

Numbers n such that S000010(n) = 1.

T. D. Noe, Plot of 68 terms

T. D. Noe, Table of 68 terms

Eric W. Weisstein, MathWorld: Primitive Prime Factor

(Mma) d = 5; f2[n_] := Cyclotomic[2*n, d]/Cyclotomic[n, d]; Join[{0}, Select[Range[1000], PrimePowerQ[f2[#]/GCD[f2[#], #]] &]]

Cf. S000010.

nonn,hard

T. D. Noe, Nov 21 2014

© Tony D Noe 2014-2015