A005119 Computation of Infinitesimal Generator

[pauldhanna at juno.com]

Seqfans, 
      How does one compute the terms of A005119: 
"Infinitesimal generator of x(x+1)." 
1, 1, 3, 16, 124, 1256, 15576, 226248, 3729216, 68179968, 1361836800, 
29501349120, 693638208000, 17815908096000, 502048890201600,
15388268595840000 
 
There is no other formula nor e.g.f. and I do not have access to the
reference. 
Thanks for any help, 
      Paul