A035243 Positive numbers of the form x^2+xy+5y^2 (discriminant -19).

1, 4, 5, 7, 9, 11, 16, 17, 19, 20, 23, 25, 28, 35, 36, 43, 44, 45, 47, 49, 55, 61, 63, 64, 68, 73, 76, 77, 80, 81, 83, 85, 92, 95, 99, 100, 101, 112, 115, 119, 121, 125, 131, 133, 137, 139, 140, 144, 149, 153, 157, 161, 163, 169, 171, 172, 175, 176, 180, 187, 188, 191, 196, 197, 199, 207, 209, 215, 220, 225, 229, 233, 235, 239, 244, 245, 251, 252, 253, 256

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn

Comments

Indices of nonzero terms in expansion of Dirichlet series Product_p (1-(Kronecker(m,p)+1)*p^(-s)+Kronecker(m,p)*p^(-2s))^(-1) for m= -19 (A035171). [amended by Georg Fischer, Sep 03 2020]

Crossrefs

Cf. A035171.

For primes see A106863.

Programs

PARI

m=-19; select(x -> x, direuler(p=2,101,1/(1-(kronecker(m,p)*(X-X^2))-X)), 1) \\ Fixed by Andrey Zabolotskiy, Sep 03 2020

Extensions

Edited by N. J. A. Sloane, Jun 01 2014