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URL: https://oeis.org/A244780

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A244780
Positive numbers primitively represented by the binary quadratic form (1, 1, 3).
5
1, 3, 5, 9, 11, 15, 23, 25, 27, 31, 33, 37, 45, 47, 53, 55, 59, 67, 69, 71, 75, 81, 89, 93, 97, 99, 103, 111, 113, 115, 125, 135, 137, 141, 155, 157, 159, 163, 165, 177, 179, 181, 185, 191, 199, 201, 207, 213, 223, 225, 229, 235, 243, 251, 253, 257, 265, 267
OFFSET
1,2
COMMENTS
Discriminant = -11.
LINKS
N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)
MAPLE
# Function PriRepBQF in A244779.
A244780_list := n -> PriRepBQF(1, 1, 3, n); A244780_list(267);
MATHEMATICA
Reap[For[n = 1, n < 1000, n++, r = Reduce[x^2 + x y + 3 y^2 == n, {x, y}, Integers]; If[r =!= False, If[AnyTrue[{x, y} /. {ToRules[r /. C[1] -> 0]}, CoprimeQ @@ # &], Sow[n]]]]][[2, 1]] (* Jean-François Alcover, Oct 31 2016 *)
CROSSREFS
Sequence in context: A233970 A169780 A233760 * A024903 A382262 A322957
KEYWORD
nonn
AUTHOR
Peter Luschny, Jul 06 2014
STATUS
approved