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 A138379 #4 Sep 18 2011 16:19:46
%S A138379 1,6,60,888,18120,485280,16445520,685722240,34411184640,2041544736000,
%T A138379 141106965753600,11223409849344000,1016591564596608000,
%U A138379 103921686070339737600,11896153817325313536000
%N A138379 Number of embedded coalitions in an n-person game where the position of the individual player is important.
%C A138379 See A005493 for references and links.
%F A138379 a(1) = 1 * SUM(i=0 to 0)combination(1,i) = 1, a(2) = 2 * SUM(i=0 to 1)combination(2,i) = 6, a(n) = n![SUM(i=2 to n-1) combination(n,i) * {SUM(j=1 to i-1) * a(j)/j! } + SUM(i=0 to n-1) combination(n,i)], for n > 2.
%e A138379 a(1) = 1 * SUM(i=0 to 0)combination(1,i) = 1,
%e A138379 a(2) = 2 * SUM(i=0 to 1)combination(2,i) = 6,
%e A138379 a(3) = 3![combination(3,2) * a(1)/1! + combination(3,2) + combination(3,1) + combination(3,0)] = 60,
%e A138379 a(4) = 4![combination(4,3) * {a(2)/2! + a(1)/1!} + combination(4,2) * a(1)/1! + combination(4,3) + combination(4,2) + combination(4,1) + combination(4,0)] = 888,
%e A138379 a(5) = 5![combination(5,4) * {a(3)/3! + a(2)/2! + a(1)/1!} + combination(5,3) * {a(2)/2! + a(1)/1!} + combination(5,2) * a(1)/1! + combination(5,4) + combination(5,3) + combination(5,2) + combination(5,1) + combination(5,0)] = 18120.
%K A138379 nonn
%O A138379 1,2
%A A138379 David Yeung (wkyeung(AT)hkbu.edu.hk), May 08 2008