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 A027089 #12 Jun 24 2020 14:05:11 %S A027089 1,5,14,39,108,299,828,2299,6401,17875,50062,140601,395933,1117737, %T A027089 3162812,8969267,25487555,72565339,206969662,591304797,1691991626, %U A027089 4848703909,13914119144,39980978277,115023510495,331303274449 %N A027089 a(n) = A027082(n, 2n-2). %F A027089 Conjecture: D-finite with recurrence -(n+2)*(244*n-1065)*a(n) +3*(n+1)*(422*n -1703)*a(n-1) +2*(-359*n^2 +1211*n -1420)*a(n-2) +2*(-1174*n^2 +6319*n -7410)*a(n-3) +(-760*n^2 +2173*n +1616)*a(n-4) +(-502*n^2 +2245*n -1123)*a(n-5) +6*(23*n-67) *(n-5)*a(n-6)=0. - _R. J. Mathar_, Jun 24 2020 %Y A027089 Cf. A027082. %K A027089 nonn %O A027089 2,2 %A A027089 _Clark Kimberling_