A379639 Smallest primitive prime factor of 6^n-1.

5, 7, 43, 37, 311, 31, 55987, 1297, 19, 11, 23, 13, 3433, 29, 1171, 17, 239, 46441, 191, 241, 1822428931, 51828151, 47, 1678321, 18198701, 53, 163, 421, 7369130657357778596659, 1950271, 5333, 353, 67, 190537, 71, 73, 149, 1787, 3143401, 41, 8648131, 2527867231

Offset: 1

Author

Sean A. Irvine, Dec 28 2024

Keywords

• nonn

Comments

Also, smallest prime p such that 1/p has senary period n.

Links

• Max Alekseyev, Table of n, a(n) for n = 1..436 (first 420 terms from Sean A. Irvine)

Crossrefs

Cf. A112927 (base 2), A143663 (base 3), A112092 (base 4), A143665 (base 5), A379639 (base 6), A379640 (base 7), A379641 (base 8), A379642 (base 9), A007138 (base 10), A379644 (base 11), A252170 (base 12).

Cf. A274907.

Programs

PARI

listap(nn) = {prf = []; for (n=1, nn, vp = (factor(6^n-1)[, 1])~; f = setminus(Set(vp), Set(prf)); prf = concat(prf, f); print1(vecmin(Vec(f)), ", "); ); }