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 A181644 #14 Nov 20 2022 10:52:52 %S A181644 1,1,1,2,1,1,6,3,1,1,22,11,4,1,1,92,46,17,5,1,1,426,213,79,24,6,1,1, %T A181644 2150,1075,399,122,32,7,1,1,11708,5854,2173,665,176,41,8,1,1,68282, %U A181644 34141,12673,3878,1027,242,51,9,1,1,423948,211974,78683,24075,6373,1502 %N A181644 Eigentriangle for the Catalan triangle (c(x), xc(x)), A033184. %C A181644 First column is essentially A091768. Inverse of A181645. %H A181644 Paul Barry, <a href="http://arxiv.org/abs/1107.5490">Invariant number triangles, eigentriangles and Somos-4 sequences</a>, arXiv preprint arXiv:1107.5490 [math.CO], 2011. %e A181644 Triangle begins %e A181644 1, %e A181644 1, 1, %e A181644 2, 1, 1, %e A181644 6, 3, 1, 1, %e A181644 22, 11, 4, 1, 1, %e A181644 92, 46, 17, 5, 1, 1, %e A181644 426, 213, 79, 24, 6, 1, 1, %e A181644 2150, 1075, 399, 122, 32, 7, 1, 1, %e A181644 11708, 5854, 2173, 665, 176, 41, 8, 1, 1 %Y A181644 Cf. A033184, A091768, A181645. %K A181644 easy,nonn,tabl %O A181644 0,4 %A A181644 _Paul Barry_, Nov 03 2010