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 A091553 #5 Oct 12 2012 14:40:20 %S A091553 1,704,300096,113762304,41644855296,15075073327104,5436979231850496, %T A091553 1958506906364411904,705205813266345885696,253891292037560301256704, %U A091553 91402929045514567230160896,32905302125838589613523861504 %N A091553 Third column (k=6) sequence of array A090214 ((4,4)-Stirling2) divided by 72. %F A091553 a(n)= A090214(n+2, 6)/72, n>=0. %F A091553 a(n)= (15*(6*5*4*3)^n - 10*(5*4*3*2)^n + (4*3*2*1)^n)/3!. %F A091553 G.f.: (1+200*x)/product(1-fallfac(p, 4)*x, p=4..6), with fallfac(n, m) := A008279(n, m) (falling factorials). %F A091553 a(n)= ((4!)^n)*(1-2*5^(n+1)+binomial(6, 2)^(n+1))/3!. From eq.12 of the Blasiak et al. reference given in A078740 with r=4=s, k=6. %Y A091553 Cf. A089518 (third column of array (3, 3)-Stirling2 divided by 9). %K A091553 nonn,easy %O A091553 0,2 %A A091553 _Wolfdieter Lang_, Feb 13 2004