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 A055539 #8 Jul 02 2025 16:01:59
%S A055539 3,44,287,1315,4862,15511,44360,116431,284949,657696,1443853,3034549,
%T A055539 6137552,11996470,22739586,41923060,75361026,132371521,227617365,
%U A055539 383784757,635428859,1034423186,1657591966,2617279946,4075841668
%N A055539 Number of asymmetric types of (4,n)-hypergraphs without isolated nodes, under action of symmetric group S_4; asymmetric n-covers of an unlabeled 4-set.
%C A055539 Cover may include both empty sets and multiple occurrences of a subset.
%F A055539 G.f. : (1/(1-x)^16-6/((1-x)^8*(1-x^2)^4)-3/((1-x)^4*(1-x^2)^6)+8/((1-x)^4*(1-x^3)^4)+2/((1-x)^2*(1-x^2)^3*(1-x^4)^2)+6/((1-x)^4*(1-x^2)^4*(1-x^4))-8/((1-x)^2*(1-x^4)^2*(1-x^6))-4/(1-x)^8+12/(1-x)^4/(1-x^2)^2-8/(1-x)^2/(1-x^3)^2+12/(1-x)^4-12/(1-x)^2/(1-x^2)-24/(1-x)^2+24/(1-x))/24.
%e A055539 There are 3 asymmetric (4,3)-hypergraphs without isolated nodes: {{1,2},{1,2,3},{1,3,4}}, {{1,2},{1,3},{1,2,4}}, {{1},{2,3},{1,2,4}}.
%Y A055539 Cf. A005746.
%K A055539 nonn
%O A055539 3,1
%A A055539 _Vladeta Jovovic_, Jul 09 2000
%E A055539 More terms from _James Sellers_, Jul 11 2000