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 A218092 #15 Jun 27 2025 00:46:30
%S A218092 3,12,61,310,1821,11592,80963,608832,4910785,42159238,383478987,
%T A218092 3678859158,37087880753,391641822540,4319860660447,49647399946048,
%U A218092 593217470459313,7354718987639958,94445777492433515,1254196823154143190,17198114810490326713
%N A218092 Number of transitive reflexive early confluent binary relations R on n labeled elements with max_{x}(|{y : xRy}|) = 2.
%C A218092 R is early confluent iff (xRy and xRz) implies (yRz or zRy) for all x, y, z.
%D A218092 A. P. Heinz (1990). Analyse der Grenzen und Möglichkeiten schneller Tableauoptimierung. PhD Thesis, Albert-Ludwigs-Universität Freiburg, Freiburg i. Br., Germany.
%H A218092 Alois P. Heinz, <a href="/A218092/b218092.txt">Table of n, a(n) for n = 2..200</a>
%F A218092 E.g.f.: exp(x*exp(x)+x^2/2)-exp(x).
%F A218092 a(n) = A135312(n) - A000012(n).
%p A218092 egf:= exp(x*exp(x)+x^2/2)-exp(x):
%p A218092 a:= n-> n!* coeff(series(egf, x, n+1), x, n):
%p A218092 seq(a(n), n=2..30);
%t A218092 nn=22; Drop[CoefficientList[Series[Exp[x Exp[x]+x^2/2]-Exp[x],{x,0,nn}],x] Range[0,nn]!,2] (* _Harvey P. Dale_, May 03 2014 *)
%Y A218092 Column k=2 of A135313.
%K A218092 nonn
%O A218092 2,1
%A A218092 _Alois P. Heinz_, Oct 20 2012