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 A172613 #28 Sep 08 2022 08:45:50
%S A172613 1,1,48620,227873431500,21452752266265320000,
%T A172613 19010638202652030712978200000,
%U A172613 101097362223624462291180422369532000000,2392741010223442438553822446842770682716580000000,203653377853981828616656775313699668953042169048889600000000
%N A172613 a(n) = (9n)!/(9!^n).
%C A172613 From _Tilman Piesk_, Oct 30 2014: (Start)
%C A172613 Column 9 of A187783.
%C A172613 Number of permutations of a multiset that contains n different elements, each occurring 9 times.
%C A172613 Or in other words (the former title of this sequence):
%C A172613 Number of 9*n X n 0..1 arrays with row sums 1 and column sums 9.
%C A172613 (End)
%H A172613 Tilman Piesk, <a href="/A172613/b172613.txt">Table of n, a(n) for n = 0..54</a> (first 11 terms from R. H. Hardin)
%F A172613 a(n) = (9n)!/(9!^n).
%e A172613 a(3) = (9*3)!/(9!^3) = 227873431500 is the number of permutations of a multiset that contains 3 different elements, each occurring 9 times, e.g., {1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3}.
%p A172613 A172613:=n->(9*n)!/(362880^n): seq(A172613(n), n=0..10); # _Wesley Ivan Hurt_, Nov 01 2014
%t A172613 Table[(9 n)! / (362880^n), {n, 0, 10}] (* _Vincenzo Librandi_, Nov 01 2014 *)
%o A172613 (Magma) [Factorial(9*n)/(362880^n): n in [0..20]]; // _Vincenzo Librandi_, Nov 01 2014
%K A172613 nonn,easy
%O A172613 0,3
%A A172613 _R. H. Hardin_, Feb 06 2010
%E A172613 Name changed by _Tilman Piesk_, Oct 30 2014