A064217 Least k such that k*7^n +/- 1 are twin primes.

4, 6, 18, 24, 138, 60, 150, 720, 150, 234, 138, 966, 138, 420, 60, 1584, 420, 60, 1830, 1134, 162, 1080, 1482, 684, 240, 10074, 3378, 3300, 2742, 984, 2400, 4050, 5262, 3510, 3378, 960, 3612, 516, 6840, 6474, 4680, 4950, 12612, 7986, 4290, 8046, 5208

Offset: 0

Author

Robert G. Wilson v, Sep 21 2001

Keywords

• nonn

Crossrefs

Cf. A063983, A064213, A064214, A064215, A064218, A064220, A064221.

Programs

Mathematica

Do[ k = 1; While[ ! PrimeQ[ k*7^n + 1 ] || ! PrimeQ[ k*7^n - 1 ], k++ ]; Print[ k ], {n, 0, 50} ]

Extensions

Offset corrected by Georg Fischer, May 01 2022