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 A046904 #10 Jul 09 2025 03:52:05 %S A046904 1,1,0,0,1,4,28,234 %N A046904 Number of isomorphism classes of posets with n points with property that there is no nonsingelton proper subset T for which x not in T implies x<T or x>T or x incomparable with every element of T. %D A046904 J. A. Wright, There are 718 6-point topologies, quasi-orderings and transgraphs, Notices Amer. Math. Soc., 17 (1970), p. 646, Abstract #70T-A106. %H A046904 J. A. Wright, <a href="/A000798/a000798_4.pdf">Letter to N. J. A. Sloane, Apr 06 1972, listing 18 sequences</a> %H A046904 <a href="/index/Pos#posets">Index entries for sequences related to posets</a> %Y A046904 A subset of the posets enumerated in A003431. Cf. A046905. %K A046904 nonn %O A046904 0,6 %A A046904 John A. Wright