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 A341359 #14 Feb 12 2021 11:38:40 %S A341359 1,1,1,1,1,2,1,1,2,5,1,1,2,5,14,1,1,2,6,15,42,1,1,2,5,26,51,132,1,1,2, %T A341359 5,30,142,188,429,1,1,2,6,14,305,882,731,1430,1,1,2,5,17,210,3955, %U A341359 5910,2950,4862,1,1,2,5,22,50,5894,57855,41610,12235,16796,1,1,2,6,30,65,2550,209146,908880,303390,51822,58786 %N A341359 Square array T(m,n) read by antidiagonals, satisfying shifted Catalan recurrences: T(m,0) = 1 and T(m,n) = Sum_{k=0..n-1} T(m,k) * T(m,(n-1-k+m) mod n) for all n > 0. %C A341359 Each column is periodic, and the period of column n divides A003418(n). %H A341359 T. Amdeberhan et al. <a href="https://mathoverflow.net/q/380482">Sequences generated by sum & product of terms (with rotating indices): combinatorial?</a>, 2021. %F A341359 G.f. for row m: p_m(x) + x^(m-1)/2 * ( 1 + sqrt((1 -(4*T(m,m)+1)*x)/(1-x)) ), where p_m(x) = Sum_{n=0..m-1} T(m,n) * x^n. %e A341359 Rows of the array: %e A341359 m=0: 1, 1, 2, 5, 14, 42, 132, 429, 1430, ... %e A341359 m=1: 1, 1, 2, 5, 15, 51, 188, 731, 2950, ... %e A341359 m=2: 1, 1, 2, 6, 26, 142, 882, 5910, 41610, ... %e A341359 m=3: 1, 1, 2, 5, 30, 305, 3955, 57855, 908880, ... %e A341359 m=4: 1, 1, 2, 5, 14, 210, 5894, 209146, 8331582, ... %e A341359 m=5: 1, 1, 2, 6, 17, 50, 2550, 255050, 32007550, ... %e A341359 ... %t A341359 T[m_, 0] := 1; T[m_, n_] := T[m, n] = Sum[T[m, k] * T[m, Mod[n - 1 - k + m, n]], {k, 0, n - 1}]; Table[T[m - n, n], {m, 0, 11}, {n, 0, m}] // Flatten (* _Amiram Eldar_, Feb 09 2021 *) %Y A341359 Rows: A000108 (m=0), A181768 (m=1). %Y A341359 Columns: A000012 (n=0 and n=1), A007395 (n=2). %Y A341359 Cf. A007317, A162326, A082298,A226392, A341360 (diagonal). %K A341359 nonn,tabl %O A341359 0,6 %A A341359 _Max Alekseyev_, Feb 09 2021