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A128029
Numbers n such that (14^n - 3^n)/11 is prime.
28
2, 5, 13, 67, 2657, 3547, 15649
OFFSET
1,1
COMMENTS
All terms are primes.
There is no further term up to prime(1400)=11657. - Farideh Firoozbakht, Apr 04 2007
No other terms < 100,000.
MATHEMATICA
k=11; Select[ Prime[ Range[1, 200] ], PrimeQ[ ((k+3)^# - 3^#)/k ]& ]
PROG
(PARI) is(n)=isprime((14^n-3^n)/11) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
Cf. A028491 = numbers n such that (3^n - 1)/2 is prime. Cf. A057468 = numbers n such that 3^n - 2^n is prime. Cf. A059801 = numbers n such that 4^n - 3^n is prime. Cf. A121877 = numbers n such that (5^n - 3^n)/2 is a prime. Cf. A128024, A128025, A128026, A128027, A128028, A128030, A128031, A128032.
Sequence in context: A013497 A260232 A262366 * A215167 A349735 A081650
KEYWORD
hard,nonn
AUTHOR
Alexander Adamchuk, Feb 11 2007
EXTENSIONS
More terms from Farideh Firoozbakht, Apr 04 2007
Added term a(7)=15649 by Robert Price, Sep 12 2011
STATUS
approved