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 A027116 #10 Oct 23 2019 20:32:55 %S A027116 7,23,56,120,241,467,886,1660,3087,5715,10552,19452,35825,65943, %T A027116 121342,223240,410663,755391,1389448,2555664,4700673,8645963,15902486, %U A027116 29249316,53797967,98949979,181997480,334745652,615693345 %N A027116 a(n) = A027113(n, n+3). %F A027116 Conjectures from _Colin Barker_, Feb 20 2016: (Start) %F A027116 a(n) = 3*a(n-1)-2*a(n-2)-a(n-4)+a(n-5) for n>7. %F A027116 G.f.: x^3*(7+2*x+x^2-2*x^3) / ((1-x)^2*(1-x-x^2-x^3)). %F A027116 (End) %K A027116 nonn %O A027116 3,1 %A A027116 _Clark Kimberling_