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 A082765 #15 Mar 01 2015 15:14:03
%S A082765 1,4,45,1282,70177,6239016,817234189,147950506390,35370826189857,
%T A082765 10791515504716012,4091225768720823181,1886585105032464025674,
%U A082765 1039774852573506696192385,674970732343624159361034832
%N A082765 Trinomial transform of the factorial numbers (A000142).
%C A082765 Number of ways to use the elements of {1,..,k}, 0<=k<=2n, once each to form a sequence of n (possibly empty) lists, each of length at most 2. - Bob Proctor, Apr 18 2005
%H A082765 Robert A. Proctor, <a href="http://arxiv.org/abs/math.CO/0606404">Let's Expand Rota's Twelvefold Way For Counting Partitions!</a>, arXiv:math.CO/0606404, Jan 05, 2007
%H A082765 <a href="/index/Par#partN">Index entries for related partition-counting sequences</a>
%F A082765 a(n) = Sum[ Trinomial[n, k] k!, {k, 0, 2n} ] where Trinomial[n, k] = trinomial coefficients (A027907)
%F A082765 Integral_{x=0..infinity} (x^2+x+1)^n*exp(-x) dx - _Gerald McGarvey_, Oct 14 2006
%Y A082765 a(n) = Sum[C(n, k)*A099022(k), 0<=k<=n]
%Y A082765 Replace "sequence" by "collection" in comment: A105747.
%Y A082765 Replace "lists" by "sets" in comment: A003011.
%K A082765 easy,nonn
%O A082765 0,2
%A A082765 _Emanuele Munarini_, May 21 2003