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A211409 Numbers n such that (9^n + 4^n)/13 is prime. 1
3, 5, 7, 11, 17, 19, 41, 53, 109, 167, 2207, 3623, 5059, 5471, 7949, 21211, 32993, 60251 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are prime.

The next element, a(19), is greater than 10^5.

LINKS

Table of n, a(n) for n=1..18.

MATHEMATICA

Select[ Prime[ Range[1, 100000] ], PrimeQ[ (9^# + 4^#)/13 ]& ]

PROG

(PARI) is(n)=ispseudoprime((9^n+4^n)/13) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

cf. A181141, A128339, A057175, A125956, A187819.

Sequence in context: A235476 A094342 A045397 * A152998 A222176 A108539

Adjacent sequences:  A211406 A211407 A211408 * A211410 A211411 A211412

KEYWORD

more,nonn

AUTHOR

Robert Price, Feb 09 2013

STATUS

approved

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Last modified May 26 00:04 EDT 2019. Contains 323576 sequences. (Running on oeis4.)