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A004628
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Divisible only by primes congruent to 7 mod 8.
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1
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1, 7, 23, 31, 47, 49, 71, 79, 103, 127, 151, 161, 167, 191, 199, 217, 223, 239, 263, 271, 311, 329, 343, 359, 367, 383, 431, 439, 463, 479, 487, 497, 503, 529, 553, 599, 607, 631, 647, 713, 719, 721, 727, 743
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OFFSET
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1,2
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LINKS
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MATHEMATICA
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ok[1]=True; ok[n_]:=And@@(Mod[#, 8]==7&)/@FactorInteger[n][[All, 1]]; Select[Range[3000], ok] (* Vincenzo Librandi, Aug 20 2012 *)
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PROG
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(Magma) [n: n in [1..1000] | forall{d: d in PrimeDivisors(n) | d mod 8 eq 7}]; // Vincenzo Librandi, Aug 20 2012
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CROSSREFS
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KEYWORD
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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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