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 A289653 #14 Dec 08 2023 16:26:34
%S A289653 1,1,1,4,12,40,130,427,1428,4860,16794,58784,208010,742898,2674438,
%T A289653 9694843,35357668,129644788,477638698,1767263188,6564120418,
%U A289653 24466267018,91482563638,343059613648,1289904147322,4861946401450,18367353072150,69533550916002,263747951750358
%N A289653 Catalan numbers - 2 (A120304) with first four terms changed to 1,1,1,4.
%C A289653 Related to number of mesh patterns of length 2 that avoid the pattern 321.
%H A289653 Murray Tannock, <a href="https://skemman.is/bitstream/1946/25589/1/msc-tannock-2016.pdf">Equivalence classes of mesh patterns with a dominating pattern</a>, MSc Thesis, Reykjavik Univ., May 2016. See Appendix B2.
%t A289653 Join[{1,1,1,4},CatalanNumber[Range[4,30]]-2] (* _Paolo Xausa_, Dec 08 2023 *)
%Y A289653 A variant of A120304.All of A000108, A001453, A246604, A273526, A120304, A289615, A289616, A289652, A289653, A289654 are very similar sequences.
%K A289653 nonn
%O A289653 1,4
%A A289653 _N. J. A. Sloane_, Jul 09 2017