A337430 Numbers k such that the largest prime factor of 2^k - 1 is less than the largest prime factor of 2^k + 1.

2, 4, 6, 8, 10, 11, 12, 15, 16, 18, 20, 21, 22, 23, 24, 25, 28, 29, 30, 32, 36, 38, 39, 40, 41, 42, 43, 44, 45, 47, 48, 50, 52, 53, 54, 55, 56, 57, 58, 60, 63, 64, 66, 67, 68, 70, 71, 72, 73, 75, 76, 79, 80, 81, 84, 85, 87, 88, 90, 91, 92, 94, 95, 96, 98, 99, 100

Offset

1,1

Links

Table of n, a(n) for n=1..67.

Prog

(PARI) for(n=2, 100, my(p=vecmax(factor(2^n-1)[, 1]), q=vecmax(factor(2^n+1)[, 1])); if(p<q, print1(n, ", ")))

Crossrefs

Cf. A002587, A005420, A337431 (complement).

Sequence in context: A153170 A067030 A072427 * A050420 A214671 A291171

Adjacent sequences: A337427 A337428 A337429 * A337431 A337432 A337433

Keyword

nonn

Author

Hugo Pfoertner, Sep 23 2020

Status

approved