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 A055315 #31 Sep 08 2022 08:45:01
%S A055315 4,60,720,8400,100800,1270080,16934400,239500800,3592512000,
%T A055315 57081024000,958961203200,16999766784000,317328979968000,
%U A055315 6224529991680000,128047474114560000,2757288942600192000,62039001208504320000,1456091851893719040000,35593356379624243200000
%N A055315 Number of labeled trees with n nodes and 3 leaves.
%H A055315 Vincenzo Librandi, <a href="/A055315/b055315.txt">Table of n, a(n) for n = 4..200</a>
%H A055315 <a href="/index/Tra#trees">Index entries for sequences related to trees</a>
%F A055315 a(n) = (n!/3!)*stirling2(n-2, n-3). - _Vladeta Jovovic_, Jan 28 2004
%F A055315 a(n) = n! * (n-3)*(n-2)/12. - _Vaclav Kotesovec_, Jul 25 2014
%F A055315 E.g.f.: x*(x/(1-x))^3/3! - _Geoffrey Critzer_, Sep 19 2017
%p A055315 a:=n->sum((n-j)*n!/3!, j=3..n): seq(a(n), n=4..19); # _Zerinvary Lajos_, Apr 29 2007
%t A055315 Table[n!*(n-3)*(n-2)/12,{n,4,20}] (* _Vaclav Kotesovec_, Jul 25 2014 *)
%o A055315 (Magma) [Factorial(n)*(n-3)*(n-2)/12: n in [4..25]]; // _Vincenzo Librandi_, Jul 25 2014
%o A055315 (PARI) for(n=4,30, print1(n!*(n-3)*(n-2)/12, ", ")) \\ _G. C. Greubel_, Feb 07 2018
%Y A055315 Column 3 of A055314.
%K A055315 nonn
%O A055315 4,1
%A A055315 _Christian G. Bower_, May 11 2000