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 A026984 #8 Oct 20 2019 22:02:45
%S A026984 1,10,68,394,2011,10258,47327,229186,1007891,4752128,20351196,
%T A026984 94455408,398021603,1828645056,7624936963,34786976248,144011195937,
%U A026984 653694082256,2692363924059,12174658758744,49956496140401,225233631148500,921619221445645,4145493852959640,16926389947869331
%N A026984 a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026670.
%K A026984 nonn
%O A026984 3,2
%A A026984 _Clark Kimberling_
%E A026984 More terms from _Sean A. Irvine_, Oct 20 2019