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Search: id:A094712
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| A094712 |
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Primes that are not the sum of three positive squares. |
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+0
3
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| 2, 5, 7, 13, 23, 31, 37, 47, 71, 79, 103, 127, 151, 167, 191, 199, 223, 239, 263, 271, 311, 359, 367, 383, 431, 439, 463, 479, 487, 503, 599, 607, 631, 647, 719, 727, 743, 751, 823, 839, 863, 887, 911, 919, 967, 983, 991
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Except for primes 2, 5, 13 and 37, this sequence consists all primes p such that p = 7 (mod 8). The density of these primes is 0.25.
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MATHEMATICA
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lst={}; lim=32; Do[n=a^2+b^2+c^2; If[n<lim^2 && PrimeQ[n], lst=Union[lst, {n}]], {a, lim}, {b, a, Sqrt[lim^2-a^2]}, {c, b, Sqrt[lim^2-a^2-b^2]}]; Complement[Prime[Range[PrimePi[lst[[ -1]]]]], lst]
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CROSSREFS
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Cf. A085317 (primes that are the sum of three positive squares).
Sequence in context: A032719 A045355 A165319 this_sequence A095281 A106889 A155028
Adjacent sequences: A094709 A094710 A094711 this_sequence A094713 A094714 A094715
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KEYWORD
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nonn
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AUTHOR
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T. D. Noe (noe(AT)sspectra.com), May 21 2004
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