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A128345 Numbers n such that (8^n - 5^n)/3 is prime. 18
2, 19, 1021 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

All terms are primes.

No further terms up to 5000 [from Harvey P. Dale, Mar 23 2011]

MATHEMATICA

k=8; Do[p=Prime[n]; f=(k^p-5^p)/(k-5); If[ PrimeQ[f], Print[p] ], {n, 1, 200}]

Select[Range[5000], PrimeQ[(8^#-5^#)/3]&]  (* From Harvey P. Dale, Mar 23 2011 *)

CROSSREFS

Cf. A062572, A128344, A128346, A128347, A128348, A128349, A128350, A128351, A128352, A128353, A128354. Cf. A004061, A082182, A121877, A059802. Cf. A057171, A082387, A122853, A128335, A128336, A128337, A128338, A128339, A128340, A128341, A128342.

Sequence in context: A024228 A015191 A165937 * A013052 A012956 A012976

Adjacent sequences:  A128342 A128343 A128344 * A128346 A128347 A128348

KEYWORD

bref,hard,more,nonn

AUTHOR

Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 27 2007

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Last modified February 17 18:32 EST 2012. Contains 206071 sequences.