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

1,1

Comments

All terms are prime.

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

Links

Table of n, a(n) for n=1..13.

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A137745 A005021 A067325 * A347311 A121525 A163872

Adjacent sequences: A273596 A273597 A273598 * A273600 A273601 A273602

Keyword

nonn,more,hard

Author

Tim Johannes Ohrtmann, May 26 2016

Status

approved