A243176 Numbers of the form x^2+xy+8y^2.

0, 1, 4, 8, 9, 10, 14, 16, 20, 25, 28, 31, 32, 35, 36, 38, 40, 47, 49, 50, 56, 64, 67, 70, 72, 76, 80, 81, 82, 90, 95, 98, 100, 112, 118, 121, 124, 125, 126, 128, 131, 133, 140, 142, 144, 149, 152, 160, 164, 169, 173, 175, 180, 188, 190, 194, 196, 200, 202, 205, 206, 214, 218, 224, 225, 226, 227, 236, 245, 248, 250, 252, 256, 266, 268, 279, 280, 283, 284, 287

Offset

1,3

Comments

Discriminant -31.

Links

Table of n, a(n) for n=1..80.

N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

Mathematica

ofTheFormQ[n_] := Reduce[n == x^2 + x*y + 8*y^2, {x, y}, Integers] =!= False; Select[Range[0, 300], ofTheFormQ] (* Jean-François Alcover, Jun 04 2014 *)

Crossrefs

Primes: A033221.

Sequence in context: A164923 A141608 A367768 * A094906 A312829 A078542

Adjacent sequences: A243173 A243174 A243175 * A243177 A243178 A243179

Keyword

nonn

Author

N. J. A. Sloane, Jun 02 2014

Status

approved