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A247260 Numbers n such that 5*6^n + 1 is prime. 5
1, 2, 4, 17, 136, 147, 203, 590, 754, 964, 970, 1847, 2031, 2727, 2871, 5442, 7035, 7266, 11230, 23307, 27795, 34152, 42614, 127206, 133086 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(26) > 2*10^5.

LINKS

Table of n, a(n) for n=1..25.

MATHEMATICA

Do[ If[ PrimeQ[5*6^n + 1], Print[n]], {n, 0, 200000}]

PROG

(PARI)

for(n=0, 2*10^5, if(ispseudoprime(5*6^n+1), print1(n, ", "))) \\ Derek Orr, Sep 10 2014

CROSSREFS

Cf. A079906.

Sequence in context: A009319 A009323 A307125 * A048872 A063800 A207137

Adjacent sequences:  A247257 A247258 A247259 * A247261 A247262 A247263

KEYWORD

nonn,hard,more

AUTHOR

Robert Price, Sep 10 2014

STATUS

approved

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Last modified August 21 06:54 EDT 2019. Contains 326162 sequences. (Running on oeis4.)