A094712 Primes that are not the sum of three positive squares.

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

Offset

1,1

Comments

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.

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10000

Mathematica

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]

Crossrefs

Cf. A085317 (primes that are the sum of three positive squares).

Sequence in context: A045355 A252281 A165319 * A095281 A106889 A155028

Adjacent sequences: A094709 A094710 A094711 * A094713 A094714 A094715

Keyword

nonn

Author

T. D. Noe, May 21 2004

Status

approved