User blog comment:Googleaarex/Factorial N-ational/@comment-25371339-20140918003952/@comment-5029411-20140919211309

n!1(1,2)2 = n!1(n)2

n!1(2,2)2 = n!1(1,2)1(1,2)...1(1,2)1(1,2)2 with n 1's

n!1(1,3)2 = n!1(n,2)2

n!1(1,1,2)2 = n!1(1,n)2

n!1(1(2)2)2 = n!1(1,1...1,1,2)2 with n 1's inside 12

n!1(1(1(2)2)2)2 = n!1(1(1,1...1,1,2)2)2 with n 1's inside 1(12)2

End of extension