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 A368298 #10 Dec 20 2023 19:06:09 %S A368298 1,1,53,490614,930744290905,386735380538157813864, %T A368298 36494318768452684668237864399892, %U A368298 800075179375382235705309991148469060609055210,4138855242465150993428071754285859188133806122546895149328625,5109461743591866972924602083859433690113667142460933537037028649653229023827000 %N A368298 a(n) is the permanent of the n-th order Hankel matrix of Catalan numbers M(n) whose generic element is given by M(i,j) = A000108(i+j+n) with i,j = 0, ..., n-1. %H A368298 Wikipedia, <a href="https://en.wikipedia.org/wiki/Hankel_matrix">Hankel matrix</a>. %e A368298 a(3) = 490614: %e A368298 5, 14, 42; %e A368298 14, 42, 132; %e A368298 42, 132, 429. %p A368298 with(LinearAlgebra): %p A368298 C:= proc(n) option remember; binomial(2*n, n)/(n+1) end: %p A368298 a:= n-> `if`(n=0, 1, Permanent(Matrix(n, (i, j)-> C(i+j+n-2)))): %p A368298 seq(a(n), n=0..10); # _Alois P. Heinz_, Dec 20 2023 %t A368298 a[n_]:=If[n==0, 1, Permanent[Table[CatalanNumber[i+j+n], {i, 0, n-1}, {j, 0, n-1}]]]; Array[a,10,0] %Y A368298 Cf. A000108, A355400. %Y A368298 Diagonal of A368025. %K A368298 nonn %O A368298 0,3 %A A368298 _Stefano Spezia_, Dec 20 2023