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 A210726 #9 Aug 22 2015 22:44:19 %S A210726 1,2,4,9,22,59,169,506,1577,5078,16729,56098,190981,658442,2294164, %T A210726 8066363,28588554,102036631,366458118,1323463507,4803734390, %U A210726 17515357533,64128879398,235682969485,869175349090,3215674910037,11932102898252,44396448313385,165608308422048,619217961493403,2320410595131693,8713343724905902,32782954997996347,123567462151713252,466559336920866937,1764469819249171154 %N A210726 a(2)=1, a(3)=2; thereafter a(n) = 2a(n-1)-a(n-2)+A046919(n). %C A210726 According to Riordan (1968), this is the number of possible score sequences in a tournament with n nodes, but the latter is given by A000571, which is a different sequence. %H A210726 J. Riordan, <a href="http://dx.doi.org/10.1016/S0021-9800(68)80032-8">The number of score sequences in tournaments</a>, J. Combin. Theory, 5 (1968), 87-89. %Y A210726 Cf. A046919. %K A210726 nonn %O A210726 2,2 %A A210726 _N. J. A. Sloane_, May 09 2012