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A096453
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Primes p such that the number of primes q, 5 <= q < p, congruent to 1 mod 3, is two less than the number of such primes congruent to 2 mod 3.
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1
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31, 59, 67, 73, 97, 103, 109, 127, 137, 149, 157, 179, 191, 197, 211, 241, 257, 347, 353, 379, 389, 401, 419, 431, 439, 449, 461, 467, 761, 773, 797, 1787, 1801, 1823, 1847, 1867, 1873, 1879, 1901, 3761, 9203, 198479, 198593
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OFFSET
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1,1
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LINKS
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MAPLE
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ct := -2: q:=2: for n from 2 to 20000 do p:=q: q:=ithprime(n): ct:=ct+`if`(p mod 3 = 1, -1, 1): if(ct=2)then printf("%d, ", q): fi: od: # Nathaniel Johnston, Jun 16 2011
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MATHEMATICA
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npc1Q[n_]:=Module[{tot=PrimePi[n]-3, c}, c=Count[Prime[Range[3, tot+2]], _?(Mod[ #, 3]==1&)]; c==tot/2-1]; Select[Prime[Range[18000]], npc1Q] (* Harvey P. Dale, Aug 22 2013 *)
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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