A301369 Numbers k such that (9^k + 7^k)/16 is prime.

3, 107, 197, 2843, 3571, 4451, 31517

Offset

1,1

Comments

All terms are prime.

The corresponding primes are 67, 79401467172644850007356716446663549450843749853576087044440771380676673442288169290888310265443988907, ...

Links

Table of n, a(n) for n=1..7.

Maple

select(n->isprime((9^n+7^n)/16), [seq(n, n=1..10000, 2)]); # Muniru A Asiru, Mar 27 2018

Mathematica

Select[Range[1, 10000], PrimeQ[(9^n+7^n)/16] &]

Prog

(PARI) forprime(n=3, 10000, if(isprime((9^n+7^n)/16), print1(n, ", ")))
(Magma) [n: n in [1..10000] |IsPrime((9^n+7^n)/16)]

Crossrefs

Cf. A057175, A125956, A211409, A128339, A187819.

Sequence in context: A245657 A139921 A176807 * A142509 A023325 A094200

Adjacent sequences: A301366 A301367 A301368 * A301370 A301371 A301372

Keyword

nonn,more,hard

Author

Tim Johannes Ohrtmann, Mar 19 2018

Extensions

a(7) from Michael S. Branicky, Apr 29 2023

Status

approved