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A204323 Numbers n such that 4*7^n + 1 is prime. 0
0, 1, 2, 3, 6, 7, 10, 11, 17, 38, 65, 133, 150, 502, 537, 894, 6442, 16474, 23642, 40894, 94133, 101335, 135737, 224437, 254621, 266782 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..26.

MATHEMATICA

Select[Range[0, 2000], PrimeQ[4*7^#+1]&]

CROSSREFS

Sequence in context: A014689 A117206 A026443 * A278965 A032858 A181498

Adjacent sequences:  A204320 A204321 A204322 * A204324 A204325 A204326

KEYWORD

nonn

AUTHOR

José María Grau Ribas, Jan 14 2012

EXTENSIONS

a(17)-a(26) from Predrag Kurtovic, May 24 2015

STATUS

approved

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Last modified December 8 20:44 EST 2016. Contains 278950 sequences.