A186112 Numbers k such that 3*6^k + 1 is prime.
1, 2, 4, 6, 7, 8, 11, 15, 26, 29, 50, 66, 122, 225, 272, 275, 308, 390, 992, 1201, 2520, 15812, 17419, 29328, 41852
Offset: 1
Keywords
Examples
15 is in the sequence because 3*6^15+1=1410554953729 is prime.
Programs
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PARI
select(n->ispseudoprime(3*6^n+1),vector(10^4,i,i)) \\ Charles R Greathouse IV, Feb 13 2011
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PFGW
ABC2 3*6^$a+1 a: from 1 to 50000
Extensions
a(14), a(15), a(17) added by D. S. McNeil, Feb 12 2011
a(20)-a(25) from Charles R Greathouse IV, Feb 13 2011 to Feb 14 2011
Comments