S000051


Irregular table of primitive prime factors of 9^n + 1.

2, 5, 41, 73, 17, 193, 1181, 6481, 29, 16493, 21523361, 530713, 42521761, 5501, 570461, 97, 577, 769, 53, 4795973261, 430697, 647753, 47763361, 926510094425921, 956353, 1743831169, 282429005041, 5301533, 25480398173, 14401, 128653413121, 2857, 109688713, 89

1

S000051

T. D. Noe, Plot of irregular table up to n = 96

T. D. Noe, Table up to n = 96

(Mma) pp = {}; t = Table[f = Transpose[FactorInteger[9^n + 1]][[1]]; p = Complement[f, pp]; pp = Union[pp, p]; p, {n, 30}]; Flatten[t]

Cf. S000014 (number of primitive prime factors of 9^n + 1), S000045 (primitive prime factors of 3^n + 1).
Cf.
A002592 (largest prime factor of 9^n + 1).

nonn,tabf

T. D. Noe, May 14 2014

© Tony D Noe 2014-2015