A273599 Numbers k such that (11^k - 7^k)/4 is prime.

5, 19, 67, 107, 593, 757, 1801, 2243, 2383, 6043, 10181, 11383, 15629

Offset: 1

Author

Tim Johannes Ohrtmann, May 26 2016

Keywords

• nonn
• more
• hard

Comments

All terms are prime.

The corresponding primes: 36061, 15286922888307293287, 1483371444025889427763765389467527889556636442659800720575790059738807, ...

a(14) > 50000. - Michael S. Branicky, Nov 11 2024

Crossrefs

Cf. A005808, A210506, A128027, A216181, A128347, A273598, A273600, A273601, A062577.

Programs

Mathematica

Select[Range[1, 10000], PrimeQ[(11^# - 7^#)/4] &]

PARI

for(n=1, 10000, if(isprime((11^n - 7^n)/4), print1(n, ", ")))