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A224501 Numbers n such that (11^n + 4^n)/15 is prime. 2
7, 53, 67, 71, 443, 26497 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are prime.

a(7) > 10^5.

LINKS

Table of n, a(n) for n=1..6.

MATHEMATICA

Select[ Prime[ Range[1, 100000] ], PrimeQ[ (11^# + 4^#)/15 ]& ]

PROG

(PARI) is(n)=ispseudoprime((11^n+4^n)/15) \\ Charles R Greathouse IV, Jun 06 2017

CROSSREFS

Cf. A057178, A128341, A181141, A187819, A217095.

Sequence in context: A193881 A249349 A179517 * A241487 A236688 A239941

Adjacent sequences:  A224498 A224499 A224500 * A224502 A224503 A224504

KEYWORD

hard,nonn,more

AUTHOR

Robert Price, Apr 08 2013

STATUS

approved

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Last modified June 25 11:31 EDT 2017. Contains 288709 sequences.