A093794 Numbers n such that 8^n+7^(n-1) is prime.

2, 14, 30, 56, 96, 192, 200, 462, 540, 1400, 2756, 9030, 99702

Offset

1,1

Comments

a(14) > 10^5. - Robert Price, Feb 18 2016

Links

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

Example

14 is a member since 814+712 = 4494935521511 which is a prime number.

Mathematica

Do[ If[ PrimeQ[8^n + 7^(n - 1)], Print[n]], {n, 4000}]

Prog

(PARI) is(n)=isprime(8^n+7^(n-1)) \\ Charles R Greathouse IV, Feb 17 2017

Crossrefs

Cf. A082103, A093717, A093793, A093765, A096185, A093794, A093795, A096186.

Sequence in context: A038341 A075718 A259710 * A294561 A075490 A031301

Adjacent sequences: A093791 A093792 A093793 * A093795 A093796 A093797

Keyword

nonn

Author

Herman H. Rosenfeld (herm3(AT)pacbell.net), May 18 2004

Extensions

More terms from Robert G. Wilson v, Jun 18 2004

a(12)-a(13) from Robert Price, Feb 18 2016

Status

approved