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A273814 Numbers n such that (12^n - 7^n)/5 is prime. 1
2, 3, 7, 13, 47, 89, 139, 523, 1051 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are prime.

The corresponding primes are 19, 277, 7001653, 21379263273733, 105329145253605843602014309589572596276217801876213, ...

LINKS

Table of n, a(n) for n=1..9.

MAPLE

A273814:=n->`if`(isprime((12^n - 7^n)/5), n, NULL): seq(A273814(n), n=1..10^3); # Wesley Ivan Hurt, Jun 01 2016

MATHEMATICA

Select[Range[1, 10000], PrimeQ[(12^# - 7^#)/5] &]

PROG

(PARI) for(n=1, 10000, if(isprime((12^n - 7^n)/5), print1(n, ", ")))

CROSSREFS

Cf. A004064, A062578, A128348.

Sequence in context: A206579 A166945 A257393 * A085872 A070858 A061067

Adjacent sequences:  A273811 A273812 A273813 * A273815 A273816 A273817

KEYWORD

nonn,more,hard

AUTHOR

Tim Johannes Ohrtmann, May 31 2016

STATUS

approved

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Last modified May 25 11:55 EDT 2019. Contains 323554 sequences. (Running on oeis4.)