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A186782
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Primes of the form k*6^m-1 with k prime and m an integer.
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2
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2, 11, 17, 29, 41, 71, 101, 107, 113, 137, 173, 179, 251, 257, 281, 317, 353, 401, 431, 467, 617, 641, 647, 653, 677, 683, 761, 821, 827, 941, 977, 1181, 1193, 1361, 1373, 1433, 1511, 1613, 1697, 1877, 1901, 1907, 2081, 2153, 2237, 2273, 2297, 2333, 2381, 2411, 2591
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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5*6^1-1 = 29 is prime and therefore a term.
7*6^2-1 = 251 is prime and therefore a term.
17*6^13-1 = 222031798271 is prime and therefore a term (see also its companion in A185069).
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MATHEMATICA
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maxM = 4; p = Prime[Range[PrimePi[2*6^maxM]]]; Sort[Flatten[Table[Select[p + 1, PrimeQ[#/6^k] &], {k, 0, maxM}] - 1]] (* T. D. Noe, Feb 28 2011 *)
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PROG
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(Magma) IsA186782:=function(n); k:=n+1; while k mod 6 eq 0 do k:=(k div 6); end while; return IsPrime(k); end function; [ n: n in PrimesUpTo(3000) | IsA186782(n) ]; // Klaus Brockhaus, Mar 01 2011
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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