A187805 - OEIS

A187805 - OEIS

A187805

Numbers n such that (7^n + 6^n)/13 is prime.

7

3, 53, 83, 487, 743

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OFFSET

1,1

COMMENTS

All terms are prime.

a(6) > 10^5

LINKS

Table of n, a(n) for n=1..5.

MATHEMATICA

Select[ Prime[ Range[100000] ], PrimeQ[ (7^# + 6^#)/13 ]& ]

PROG

(PARI) is(n)=ispseudoprime((7^n+6^n)/13) \\ Charles R Greathouse IV, Feb 17 2017

CROSSREFS

Cf. A181141, A128336, A128337.

Sequence in context: A269458 A288867 A082484 * A178608 A106997 A141929

Adjacent sequences: A187802 A187803 A187804 * A187806 A187807 A187808

KEYWORD

more,hard,nonn

AUTHOR

Robert Price, Jan 06 2013

STATUS

approved