A255887 a(n) = 1 if the n-th prime is the sum of three squares, otherwise a(n) = 0.

1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1

Offset

1

Links

Table of n, a(n) for n=1..100.

MathOverflow, Primes that are the sum of three squares

Example

Prime(10) = 29 = 2^2 + 3^2 + 4^2, so a(10) = 1.

Mathematica

a[n_] := If[n == 2, 1, If[Mod[Prime[n], 8] == 7, 0, 1]]; Array[a, 100]

Crossrefs

Cf. A007522, A042998.

Sequence in context: A285671 A267773 A325321 * A359473 A181183 A295316

Adjacent sequences: A255884 A255885 A255886 * A255888 A255889 A255890

Keyword

nonn

Author

Jean-François Alcover, Mar 09 2015

Status

approved