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A231329 Numbers n such that (19^n + 4^n)/23 is prime. 0
7, 11, 211, 14461 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 25 03:10 EDT 2019. Contains 326318 sequences. (Running on oeis4.)