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 A135790 #8 Apr 06 2015 10:43:14
%S A135790 4,7,64,112,119,164,239,324,527,567,644,959,1024,1519,1792,1904,2047,
%T A135790 2500,2624,2884,3479,3824,4207,4324,4375,4879,4964,5184,5572,6647,
%U A135790 6887,7327,8119,8432,9072,9604,9639
%N A135790 Positive numbers of the form -x^4+6x^2 y^2-y^4 (where x,y are integers).
%C A135790 Squares of these numbers are of the form N^4-M^2 (where N belongs to A135786 and M to A057102). Proof uses: (x^4 - 6x^2 y^2 + y^4)^2=(x^2+y^2)^4-(4(x^3y-xy^2))^2.
%C A135790 Refers to A057102, which had an incorrect description and has been replaced by A256418. As a result the present sequence should be re-checked. - _N. J. A. Sloane_, Apr 06 2015
%t A135790 a = {}; Do[Do[w = -x^4 + 6x^2 y^2 - y^4; If[w > 0&&w<10000, AppendTo[a, w]], {x, y, 2000}], {y, 1, 2000}]; Union[a]
%Y A135790 Cf. A000404, A050803, A057102, A135784, A060803, A135786, A135787, A135789.
%K A135790 nonn
%O A135790 1,1
%A A135790 _Artur Jasinski_, Nov 29 2007