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 A278843 #8 Dec 23 2023 12:56:27 %S A278843 1,2,53,19148,97432285,7146659536022,7683122105385590481, %T A278843 122557371932066196769721048,29280740446653388021872592300048913, %U A278843 105552099397122165176384278493772205485181002,5775235099464970103806328103231969172586171168151193533 %N A278843 a(n) = permanent M_n where M_n is the n X n matrix m(i,j) = Catalan(i+j). %H A278843 Arthur T. Benjamin, Naiomi T. Cameron, Jennifer J. Quinn, and Carl R. Yerger, <a href="https://combinatorialpress.com/cn/arch/vol200/">Catalan determinants-a combinatorial approach</a>, Congressus Numerantium 200, 27-34 (2010). <a href="https://www.researchgate.net/publication/249812385_Catalan_determinants-a_combinatorial_approach">On ResearchGate</a>. %H A278843 M. E. Mays and Jerzy Wojciechowski, <a href="https://doi.org/10.1016/S0012-365X(99)00140-5">A determinant property of Catalan numbers</a>. Discrete Math. 211, No. 1-3, 125-133 (2000). %H A278843 Wikipedia, <a href="https://en.wikipedia.org/wiki/Hankel_matrix">Hankel matrix</a>. %F A278843 Det(M(n)) = n + 1 (see Mays and Wojciechowski, 2000). - _Stefano Spezia_, Dec 08 2023 %e A278843 From _Stefano Spezia_, Dec 08 2023: (Start) %e A278843 a(4) = 97432285: %e A278843 2, 5, 14, 42; %e A278843 5, 14, 42, 132; %e A278843 14, 42, 132, 429; %e A278843 42, 132, 429, 1430. %e A278843 (End) %t A278843 Flatten[{1, Table[Permanent[Table[CatalanNumber[i+j], {i, 1, n}, {j, 1, n}]], {n, 1, 14}]}] %o A278843 (PARI) C(n) = binomial(2*n, n)/(n+1); \\ A000108 %o A278843 a(n) = matpermanent(matrix(n, n, i, j, C(i+j))); \\ _Michel Marcus_, Dec 11 2023 %Y A278843 Cf. A000108, A277829, A278770, A278844. %Y A278843 Cf. A368012, A368019, A368021, A368022, A368023, A368024, A368025. %Y A278843 Column k=2 of A368026. %K A278843 nonn %O A278843 0,2 %A A278843 _Vaclav Kotesovec_, Nov 29 2016