

A128028


Numbers n such that (13^n  3^n)/10 is prime.


29




OFFSET

1,1


COMMENTS

All terms are primes.
No other terms exist < 100,000.


LINKS

Table of n, a(n) for n=1..7.


MATHEMATICA

k=10; Select[ Prime[ Range[1, 200] ], PrimeQ[ ((k+3)^#  3^#)/k ]& ]


PROG

(PARI) is(n)=isprime((13^n3^n)/10) \\ 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, A128029, A128030, A128031, A128032.
Sequence in context: A276741 A000696 A171733 * A000921 A185004 A172490
Adjacent sequences: A128025 A128026 A128027 * A128029 A128030 A128031


KEYWORD

hard,more,nonn


AUTHOR

Alexander Adamchuk, Feb 11 2007


EXTENSIONS

One more term from Farideh Firoozbakht, Apr 03 2007
a(7)=8803 from Robert Price, Aug 12 2011


STATUS

approved



