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A186106 Numbers k such that 3*6^k - 1 is prime. 1
0, 1, 2, 3, 5, 6, 9, 12, 13, 24, 41, 71, 140, 189, 190, 630, 713, 1066, 1173, 1202, 1271, 1520, 1606, 2091, 2162, 2547, 6253, 7284, 8676, 10735, 12954, 22042, 32457, 36693, 50715 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..35.

MATHEMATICA

lst={}; Do[If[PrimeQ[(3*6^n-1)], Print[n]; AppendTo[lst, n]], {n, 10^5}];

PROG

(PARI) is(n)=ispseudoprime(3*6^n-1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

See A186104 for the actual primes; cf. A185167.

Sequence in context: A032718 A086191 A074658 * A329161 A124866 A166247

Adjacent sequences:  A186103 A186104 A186105 * A186107 A186108 A186109

KEYWORD

nonn

AUTHOR

Gilbert Mozzo, Feb 12 2011

EXTENSIONS

a(17)-a(25) computed by Bruno Berselli, Feb 12 2011 and Feb 21 2011

a(26)-a(33) computed by Gilbert Mozzo, Nov 16 2011 with Mathematica

a(34)-a(35) computed by Gilbert Mozzo, Nov 08 2018 with PARI

STATUS

approved

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Last modified April 7 10:12 EDT 2020. Contains 333300 sequences. (Running on oeis4.)