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 A135797 #17 Aug 01 2025 11:08:51
%S A135797 8,41,128,136,313,353,648,656,776,1201,1241,1513,2048,2056,2176,2696,
%T A135797 3281,3321,3593,4481,5000,5008,5128,5648,7048,7321,7361,7633,8521
%N A135797 Numbers of the form x^4 + 6*x^2*y^2 + y^4 (where x,y are positive integers).
%C A135797 Squares of these numbers are of the form N^4-M^2 (where N belongs to A135786 and M to A135796). Proof uses: (x^4+6*x^2*y^2+y^4)^2 = (x^2-y^2)^4+(4*x^3*y+4*x*y^3)^2.
%C A135797 Refers to A057102, which had an incorrect description and has been replaced by A256418.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 A135797 a = {}; Do[Do[w = x^4 + 6x^2 y^2 + y^4; If[w < 10000, AppendTo[a, w]], {x, y, 1000}], {y, 1, 1000}]; Union[a]
%t A135797 (* alternate program *)
%t A135797 Union[Select[#[[1]]^4+6#[[1]]^2 #[[2]]^2+#[[2]]^4&/@Tuples[Range[ 1000],2], #<10000&]] (* _Harvey P. Dale_, Oct 07 2012 *)
%Y A135797 Cf. A000404, A050803, A057102, A135784, A060803, A135786, A135787, A135789, A135790, A135791, A135792, A135793, A135795, A135796, A135796.
%K A135797 nonn,more
%O A135797 1,1
%A A135797 _Artur Jasinski_, Nov 29 2007