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 A135302 #44 Dec 29 2021 16:37:08 %S A135302 1,0,1,0,1,1,0,1,1,1,0,1,4,1,1,0,1,13,4,1,1,0,1,62,26,4,1,1,0,1,311, %T A135302 168,26,4,1,1,0,1,1822,1416,243,26,4,1,1,0,1,11593,13897,2451,243,26, %U A135302 4,1,1,0,1,80964,153126,29922,2992,243,26,4,1,1,0,1,608833,1893180,420841,41223,2992,243,26,4,1,1 %N A135302 Square array of numbers A(n,k) (n>=0, k>=0) of transitive reflexive early confluent binary relations R on n labeled elements where |{y : xRy}| <= k for all x, read by antidiagonals. %C A135302 R is early confluent iff (xRy and xRz) implies (yRz or zRy) for all x, y, z. %D A135302 A. P. Heinz (1990). Analyse der Grenzen und Möglichkeiten schneller Tableauoptimierung. PhD Thesis, Albert-Ludwigs-Universität Freiburg, Freiburg i. Br., Germany. %H A135302 Alois P. Heinz, <a href="/A135302/b135302.txt">Antidiagonals n = 0..140, flattened</a> %F A135302 E.g.f. of column k=0: t_0(x) = 1; e.g.f. of column k>0: t_k(x) = exp (Sum_{m=1..k} x^m/m! * t_{k-m}(x)). %F A135302 A(n,k) = Sum_{i=0..k} A135313(n,i). %e A135302 Table A(n,k) begins: %e A135302 1, 1, 1, 1, 1, 1, ... %e A135302 0, 1, 1, 1, 1, 1, ... %e A135302 0, 1, 4, 4, 4, 4, ... %e A135302 0, 1, 13, 26, 26, 26, ... %e A135302 0, 1, 62, 168, 243, 243, ... %e A135302 0, 1, 311, 1416, 2451, 2992, ... %p A135302 t:= proc(k) option remember; `if`(k<0, 0, %p A135302 unapply(exp(add(x^m/m! *t(k-m)(x), m=1..k)), x)) %p A135302 end: %p A135302 A:= proc(n, k) option remember; %p A135302 coeff(series(t(k)(x), x, n+1), x, n) *n! %p A135302 end: %p A135302 seq(seq(A(d-i, i), i=0..d), d=0..15); %t A135302 t[0, _] = 1; t[k_, x_] := t[k, x] = Exp[Sum[x^m/m!*t[k-m, x], {m, 1, k}]]; a[0, 0] = 1; a[_, 0] = 0; a[n_, k_] := SeriesCoefficient[t[k, x], {x, 0, n}]*n!; Table[a[n-k, k], {n, 0, 11}, {k, 0, n}] // Flatten (* _Jean-François Alcover_, Dec 06 2013, after Maple *) %Y A135302 Columns k=0-10 give: A000007, A000012, A135312, A210911, A210912, A210913, A210914, A210915, A210916, A210917, A210918. %Y A135302 Main diagonal gives A052880. %Y A135302 A(n,n)-A(n,n-1) gives A000670. %Y A135302 Cf. A135313. %K A135302 nonn,tabl %O A135302 0,13 %A A135302 _Alois P. Heinz_, Dec 04 2007