A093795 Numbers k such that 9^k + 8^(k-1) is prime.

2, 7, 8, 31, 610, 1292, 4015, 5990, 8887, 9626, 57952, 62116, 84698

Offset: 1

Author

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

Keywords

• nonn
• more

Comments

a(14) > 10^5. - Robert Price, Mar 05 2016

Examples

			8 is a term since 9^8 + 8^7 = 45143873, which is a prime number.
		

Crossrefs

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

Programs

Mathematica

Do[ If[ PrimeQ[9^n + 8^(n - 1)], Print[n]], {n, 4000}]

PARI

is(n)=isprime(9^n+8^(n-1)) \\ Charles R Greathouse IV, Feb 17 2017

Extensions

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

a(7)-a(13) from Robert Price, Mar 05 2016