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

Author

Hugo Pfoertner, Sep 23 2020

Keywords

• nonn

Crossrefs

Cf. A002587, A005420, A337431 (complement).

Programs

PARI

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