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 A003041 M1764 #23 Oct 20 2023 22:32:16
%S A003041 2,7,24,92,388
%N A003041 Number of vacuously transitive relations on n nodes up to isomorphism.
%C A003041 A transitive relation is vacuously transitive if it does not contain any transitive triple, that is, three distinct ordered pairs (a,b), (b,c), (a,c). - _Jukka Kohonen_, Sep 17 2021
%D A003041 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A003041 H. Sharp, Jr., <a href="https://doi.org/10.1016/0012-365X(73)90081-2">Enumeration of vacuously transitive relations</a>, Discrete Math. 4 (1973), 185-196.
%e A003041 a(2)=7: The seven relations are {}, {(1,1)}, {(1,1),(2,2)}, {(2,1)}, {(1,1),(2,1)}, {(1,1),(2,1),(2,2)} and {(2,1),(2,2)}. - _Jukka Kohonen_, Sep 17 2021
%Y A003041 Cf. A347700, A348240.
%K A003041 nonn,more
%O A003041 1,1
%A A003041 _N. J. A. Sloane_
%E A003041 Clarified and offset corrected by _Jukka Kohonen_, Sep 17 2021