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A105792
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Largest prime <= numbers congruent (2,4) mod 6 (duplicates removed).
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2
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2, 3, 7, 13, 19, 23, 31, 37, 43, 47, 53, 61, 67, 73, 79, 83, 89, 97, 103, 109, 113, 127, 131, 139, 151, 157, 163, 167, 173, 181, 193, 199, 211, 223, 229, 233, 241, 251, 257, 263, 271, 277, 283, 293, 307, 313, 317, 331, 337, 349, 353, 359, 367, 373, 379, 383, 389
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OFFSET
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1,1
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COMMENTS
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Except for the first terms, largest prime p is at least < two numbers congruent (2,4) mod 6.
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LINKS
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EXAMPLE
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7 is in the sequence because 7 is the largest prime < 8 which is a number congruent (2,4) mod 6.
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MATHEMATICA
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pp[n_] := Block[{k = n}, While[ ! PrimeQ[k], k-- ]; k]; Union[pp /@ Select[Range[400], MemberQ[{2, 4}, Mod[ #, 6]] &]] (* Ray Chandler, Oct 17 2006 *)
Union[Abs[NextPrime[#, -1]&/@Select[Range[400], MemberQ[{2, 4}, Mod[ #, 6]]&]]] Harvey P. Dale, May 17 2012
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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