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 A131104 #3 Mar 30 2012 17:38:08
%S A131104 1,2,0,3,0,0,4,0,6,0,5,0,18,8,0,6,0,36,24,10,0,7,0,60,48,120,12,0,8,0,
%T A131104 90,80,420,396,14,0,9,0,126,120,1000,1512,1092,16,0,10,0,168,168,1950,
%U A131104 3720,6804,2736,18,0,11,0,216,224,3360,7380,23240,31008,6480,20,0,12,0
%N A131104 Rectangular array read by antidiagonals: a(n, k) is the number of ways to put k labeled objects into n labeled boxes so that there is one box with exactly one object (n, k >= 1).
%C A131104 Problem suggested by Brandon Zeidler. Columns 3 through 5 are A028896, A033996, 10*A007586.
%F A131104 a(n, 1) = n. For k > 1, a(n, k) = sum_{j=1..min(floor((k-1)/2), n-1)} A008299(k-1, j)*n!*k*/(n-j-1)!.
%e A131104 Array begins:
%e A131104 1 0 0 0 0 0 0
%e A131104 2 0 6 8 10 12 14
%e A131104 3 0 18 24 120 396 1092
%Y A131104 Cf. A131103, A131105, A131106, A131107.
%K A131104 easy,nonn,tabl
%O A131104 1,2
%A A131104 _David Wasserman_, Jun 14 2007, Jun 15 2007