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 A178171 #17 Jan 04 2020 14:46:22 %S A178171 1,2,8,109,3623,200522,16514461,1912959395,298569495981, %T A178171 60701549078701,15647889334180500,5003666238486522124, %U A178171 1948975409748003520112,910680909359710587298621,503845222094502583681150340,326363222435413478204610417626,245078255691857705139839897934085 %N A178171 Number of collections of nonempty subsets of an n-element set where each element appears in at most 3 subsets. %H A178171 Andrew Howroyd, <a href="/A178171/b178171.txt">Table of n, a(n) for n = 0..100</a> %Y A178171 Row n=3 of A330964. %Y A178171 At most 1 subset gives Bell numbers A000110, at most 2 subsets gives A178165. %K A178171 nonn %O A178171 0,2 %A A178171 _Daniel E. Loeb_, Dec 17 2010 %E A178171 a(7)-a(8) from _Bert Dobbelaere_, Sep 10 2019 %E A178171 Terms a(9) and beyond from _Andrew Howroyd_, Jan 04 2020