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A243188 Nonnegative numbers of the form x^2 + 6*x*y - 6*y^2. 7

%I #20 Jul 14 2019 17:24:51

%S 0,1,4,9,10,16,21,25,34,36,40,49,61,64,66,81,84,85,90,100,106,109,121,

%T 129,136,144,154,160,165,169,181,189,196,201,210,225,226,229,241,244,

%U 250,256,264,265,274,289,301,306,309,324,336,340,346,349,354,360

%N Nonnegative numbers of the form x^2 + 6*x*y - 6*y^2.

%C Discriminant 60.

%C Also numbers representable as x^2 + 8*x*y + y^2 with 0 <= x <= y. - _Gheorghe Coserea_, Jul 29 2018

%C Also numbers of the form x^2 - 15*y^2. - _Jianing Song_, Jul 31 2018

%H Gheorghe Coserea, <a href="/A243188/b243188.txt">Table of n, a(n) for n = 1..100001</a>

%H N. J. A. Sloane et al., <a href="https://oeis.org/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a> (Index to related sequences, programs, references)

%t 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]]

%Y Cf. A031363.

%Y Primes: A107152.

%K nonn

%O 1,3

%A _N. J. A. Sloane_, Jun 05 2014

%E More terms from _Colin Barker_, Apr 07 2015

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Last modified April 24 12:54 EDT 2024. Contains 371943 sequences. (Running on oeis4.)