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 A243188 Nonnegative numbers of the form x^2 + 6*x*y - 6*y^2. 6
 0, 1, 4, 9, 10, 16, 21, 25, 34, 36, 40, 49, 61, 64, 66, 81, 84, 85, 90, 100, 106, 109, 121, 129, 136, 144, 154, 160, 165, 169, 181, 189, 196, 201, 210, 225, 226, 229, 241, 244, 250, 256, 264, 265, 274, 289, 301, 306, 309, 324, 336, 340, 346, 349, 354, 360 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Discriminant 60. Also numbers representable as x^2 + 8*x*y + y^2 with 0 <= x <= y. - Gheorghe Coserea, Jul 29 2018 Also numbers of the form x^2 - 15*y^2. - Jianing Song, Jul 31 2018 LINKS Gheorghe Coserea, Table of n, a(n) for n = 1..100001 N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references) MATHEMATICA Reap[For[n = 0, n <= 200, n++, If[Reduce[ 1*x^2 + 6*x*y - 6*y^2 == n, {x, y}, Integers] =!= False, Sow[n]]]][[2, 1]] CROSSREFS Cf. A031363. Primes: A107152. Sequence in context: A329609 A340784 A260963 * A117570 A337816 A272266 Adjacent sequences: A243185 A243186 A243187 * A243189 A243190 A243191 KEYWORD nonn AUTHOR N. J. A. Sloane, Jun 05 2014 EXTENSIONS More terms from Colin Barker, Apr 07 2015 STATUS approved

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Last modified June 8 10:57 EDT 2023. Contains 363164 sequences. (Running on oeis4.)