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A210506 Numbers n such that (11^n - 2^n)/9 is prime. 10
2, 5, 11, 13, 331, 599, 18839, 23747, 24371, 29339, 32141, 67421 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are prime.

a(13) > 10^5.

LINKS

Table of n, a(n) for n=1..12.

MATHEMATICA

Select[ Prime[ Range[1, 100000] ], PrimeQ[ (11^# - 2^#)/9 ]& ]

PROG

(PARI) is(n)=isprime((11^n-2^n)/9) \\ Charles R Greathouse IV, Feb 17 2017

CROSSREFS

Cf. A004063, A028491, A057468, A059801, A121877, A128024, A128025, A128026, A128027, A128028, A128029, A128030, A128031, A128032.

Sequence in context: A020629 A224793 A272852 * A097055 A251536 A191163

Adjacent sequences:  A210503 A210504 A210505 * A210507 A210508 A210509

KEYWORD

hard,more,nonn

AUTHOR

Robert Price, Jan 25 2013

STATUS

approved

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Last modified October 17 11:44 EDT 2019. Contains 328108 sequences. (Running on oeis4.)