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A227939 Values of n such that the equation x^2 - 2*n*y^2 = n has integer solutions. 2
1, 3, 4, 9, 11, 12, 16, 19, 25, 27, 33, 36, 43, 44, 48, 49, 51, 57, 59, 64, 67, 73, 75, 76, 81, 83, 89, 99, 100, 107, 108, 121, 123, 129, 131, 132, 139, 144, 147, 163, 169, 171, 172, 176, 177, 179, 187, 192 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..440

EXAMPLE

59 appears in the sequence because the equation x^2 - 118*y^2 = 59 has integer solutions.

MATHEMATICA

Select[Range[200], Length[FullSimplify[Solve[x^2-2*#*y^2==#, {x, y}, Integers]/.C[1]->1]]>0&] (* Vaclav Kotesovec, Oct 08 2013 *)

CROSSREFS

Cf. A172000, A229848

Sequence in context: A172980 A336930 A035252 * A047459 A177943 A091380

Adjacent sequences:  A227936 A227937 A227938 * A227940 A227941 A227942

KEYWORD

nonn

AUTHOR

Colin Barker, Oct 07 2013

STATUS

approved

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Last modified October 19 09:22 EDT 2021. Contains 348074 sequences. (Running on oeis4.)