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

1,1

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)

Prog

(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)), ", "); ); }

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.

Sequence in context: A098512 A234040 A292010 * A064082 A274907 A213175

Adjacent sequences: A379635 A379637 A379638 * A379640 A379641 A379642

Keyword

nonn

Author

Sean A. Irvine, Dec 28 2024

Status

approved