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A076850 Numbers n such that (10^n + 2)/6 is prime. 0
1, 2, 3, 4, 6, 10, 12, 15, 33, 55, 56, 61, 154, 201, 462, 570, 841, 848, 1297, 1357, 2008, 2628, 2848, 3111, 6877 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Some of the larger entries may only correspond to probable primes.

a(26) > 8000. - Jon E. Schoenfield, Dec 24 2017

LINKS

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

MATHEMATICA

Select[Range[5000], PrimeQ[(10^# + 2) / 6] &] (* Vincenzo Librandi, Sep 24 2016 *)

PROG

(PARI) isok(n) = isprime((10^n + 2)/6); \\ Michel Marcus, Aug 28 2013

(MAGMA) [n: n in [0..200] |IsPrime((10^n+2) div 6)]; // Vincenzo Librandi, Sep 24 2016

CROSSREFS

Sequence in context: A070519 A177913 A098392 * A068482 A068499 A137172

Adjacent sequences:  A076847 A076848 A076849 * A076851 A076852 A076853

KEYWORD

nonn,more

AUTHOR

Ed Pegg Jr, Nov 23 2002

EXTENSIONS

More terms from Jason Earls, Nov 24 2002

a(25) from Jon E. Schoenfield, Dec 23 2017

STATUS

approved

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Last modified April 13 16:36 EDT 2021. Contains 342936 sequences. (Running on oeis4.)