This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A028927 #10 Jul 08 2025 18:56:31 %S A028927 0,3,5,6,10,12,13,19,20,21,24,26,27,35,38,40,42,45,48,52,54,59,61,69, %T A028927 70,75,76,80,83,84,90,91,96,101,104,108,115,117,118,122,125,131,133, %U A028927 138,139,140,147,150,152,157,160,166,168,171,173,180,181,182,189,192 %N A028927 Numbers represented by quadratic form with Gram matrix [ 3, 1; 1, 5 ]. %C A028927 Nonnegative integers of the form 3*x^2 + 2*x*y + 5*y^2, discriminant -56. - _Ray Chandler_, Jul 12 2014 %H A028927 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) %F A028927 a(x_i, x_j) = 3*x_i^2 + 2*x_i*x_j + 5*x_j^2, for all x_i >= 0, x_j any integer. %K A028927 nonn %O A028927 1,2 %A A028927 _N. J. A. Sloane_ %E A028927 More terms from Larry Reeves (larryr(AT)acm.org), Mar 28 2000