a(n) = n*A052530(n)/2.

Terms

a(0) =0a(1) =3a(2) =16a(3) =75a(4) =336a(5) =1463a(6) =6240a(7) =26199a(8) =108640a(9) =445995a(10) =1815792a(11) =7341347a(12) =29505840a(13) =117982815a(14) =469672384a(15) =1862393775a(16) =7359403968a(17) =28991540051a(18) =113892526800a(19) =446305331451