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A096186
Numbers n such that 10^n+9^(n-1) is prime.
20
1, 2, 4, 9, 12, 14, 19, 26, 28, 72, 79, 273, 565, 990, 1166, 2205, 4212, 5340, 5562, 9877, 10297, 14316, 35908, 48410, 61525
OFFSET
1,2
COMMENTS
a(26) > 10^5. - Robert Price, Mar 28 2016
MATHEMATICA
Do[ If[ PrimeQ[10^n + 9^(n - 1)], Print[n]], {n, 4000}]
PROG
(PARI) is(n)=isprime(10^n+9^(n-1)) \\ Charles R Greathouse IV, Feb 17 2017
KEYWORD
nonn
AUTHOR
Herman H. Rosenfeld (herm3(AT)pacbell.net) and Robert G. Wilson v, Jun 21 2004
EXTENSIONS
a(17)-a(25) from Robert Price, Mar 28 2016
STATUS
approved