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A245241
Integers n such that 6 * 7^n + 1 is prime.
3
0, 1, 4, 9, 99, 412, 2633, 5093, 5632, 28233, 36780, 47084, 53572
OFFSET
1,3
COMMENTS
All terms correspond to verified primes, that is, not merely probable primes.
a(14) > 2*10^5.
EXAMPLE
4 is in this sequence because 6 * 7^4 + 1 = 14407, which is prime.
MATHEMATICA
Select[Range[0, 200000], PrimeQ[6 * 7^# + 1] &]
KEYWORD
nonn,more
AUTHOR
Robert Price, Nov 14 2014
STATUS
approved