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A093795
Numbers k such that 9^k + 8^(k-1) is prime.
20
2, 7, 8, 31, 610, 1292, 4015, 5990, 8887, 9626, 57952, 62116, 84698
OFFSET
1,1
COMMENTS
a(14) > 10^5. - Robert Price, Mar 05 2016
EXAMPLE
8 is a term since 9^8 + 8^7 = 45143873, which is a prime number.
MATHEMATICA
Do[ If[ PrimeQ[9^n + 8^(n - 1)], Print[n]], {n, 4000}]
PROG
(PARI) is(n)=isprime(9^n+8^(n-1)) \\ Charles R Greathouse IV, Feb 17 2017
KEYWORD
nonn,more
AUTHOR
Herman H. Rosenfeld (herm3(AT)pacbell.net), May 18 2004
EXTENSIONS
More terms from Robert G. Wilson v, Jun 18 2004
a(7)-a(13) from Robert Price, Mar 05 2016
STATUS
approved