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 A001376 M3726 N1523 #18 Nov 20 2016 23:37:51
%S A001376 4,32896,3002399885885440,14178431955039103827204744901417762816,
%T A001376 15077094952775546279110805340148653909930339849938544191736262642546769920,
%U A001376 15403720522893415886546745467461576130202428237004582894538688334760691986727408991549968230000116580053960252500580634898464768
%N A001376 Relational systems on n nodes.
%D A001376 W. Oberschelp, "Strukturzahlen in endlichen Relationssystemen," in Contributions to Mathematical Logic (Proceedings 1966 Hanover Colloquium), pp. 199-213, North-Holland Publ., Amsterdam, 1968.
%D A001376 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D A001376 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A001376 W. Oberschelp, <a href="/A000662/a000662.pdf"> Strukturzahlen in endlichen Relationssystemen</a>, in Contributions to Mathematical Logic (Proceedings 1966 Hanover Colloquium), pp. 199-213, North-Holland Publ., Amsterdam, 1968. [Annotated scanned copy]
%F A001376 a(n) = Sum_{1*s_1+2*s_2+...=n} (fix A[s_1, s_2,...]/(1^s_1*s_1!*2^s_2*s_2!*...)) where fix A[s_1, s_2, ...] = 4^Sum_{i, j, k>=1} (i*j*k*s_i*s_j*s_k/lcm(i, j, k)). - _Sean A. Irvine_, Nov 20 2016
%K A001376 nonn
%O A001376 1,1
%A A001376 _N. J. A. Sloane_
%E A001376 a(5)-a(6) from _Sean A. Irvine_, Nov 20 2016