

A231329


Numbers n such that (19^n + 4^n)/23 is prime.


0




OFFSET

1,1


COMMENTS

Conjecture: All terms are prime.
a(5) > 10^5.


LINKS

Table of n, a(n) for n=1..4.


MATHEMATICA

Select[ Prime[ Range[1, 100000] ], PrimeQ[ (19^# + 4^#)/23 ]& ]


PROG

(PARI) is(n)=ispseudoprime((19^n+4^n)/23) \\ Charles R Greathouse IV, Jun 13 2017


CROSSREFS

Cf. A227049, A228558, A128075, A229612.
Sequence in context: A106716 A292791 A106818 * A322950 A201120 A164328
Adjacent sequences: A231326 A231327 A231328 * A231330 A231331 A231332


KEYWORD

hard,nonn,more


AUTHOR

Robert Price, Nov 07 2013


STATUS

approved



