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A243703 Nonnegative numbers represented by the indefinite quadratic form -x^2+13xy+9y^2. 1


%S 0,9,21,31,36,39,41,45,49,51,61,81,84,91,105,119,124,141,144,155,156,

%T 159,164,169,180,189,195,196,201,204,205,221,225,244,245,251,255,279,

%U 289,291,305,324,329,336,349,351,364,369,371,379,389,401,405,411,419

%N Nonnegative numbers represented by the indefinite quadratic form -x^2+13xy+9y^2.

%C Discriminant 205.

%H Will Jagy, <a href="/A243655/a243655.txt">C++ program Conway_Positive_All.cc to find all positive numbers represented by an indefinite binary quadratic form</a>

%H Will Jagy, <a href="/A243655/a243655_2.txt">Sample output from Conway_Positive_All.cc</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)

%o (C++, Jagy's program, see link)

%o Conway_Positive_All -1 13 9 500

%Y Primes: A243704.

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Jun 17 2014

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Last modified October 1 10:25 EDT 2022. Contains 357147 sequences. (Running on oeis4.)