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 A126564 #11 Apr 06 2021 20:16:25 %S A126564 0,0,-1,-1,0,-1,-1,0,-1,-1,0,-1,-1,0,0,-1,0,0,-1,0,0,-1,0,0,-1,-1,0, %T A126564 -1,-1,0,-1,-1,0,-1,-1,0,0,-1,0,0,-1,0,0,-1,0,0,-1,-1,0,-1,-1,0,-1,-1, %U A126564 0,-1,-1,0,0,-1,0,0,-1,0,0,-1,0,0,-1,-1,0,-1,-1,0,-1,-1,0,-1,-1,0,0,-1,0,0,-1,0,0,-1,0,0,-1,-1,0,-1,-1,0,-1,-1,0,-1,-1,0,0 %N A126564 a(n) = floor( sin(n)*cos(n) ). %F A126564 a(n) = floor(sin(n)*cos(n)). %F A126564 a(n) = floor(sin(2n)/2). [_Wesley Ivan Hurt_, Jun 22 2013] %o A126564 (PARI) a(n) = floor(sin(n)*cos(n)) %Y A126564 Cf. A000480, A000493, A126565. %K A126564 sign %O A126564 0,1 %A A126564 _Rick L. Shepherd_, Dec 27 2006