3*Volume of the root-n Waterman polyhedron of void-center type as defined in A119870.

Terms

a(0) =4a(1) =24a(2) =96a(3) =96a(4) =272a(5) =344a(6) =404a(7) =404a(8) =712a(9) =844a(10) =988a(11) =988a(12) =1156a(13) =1500a(14) =1740a(15) =1740a(16) =1992a(17) =2088a(18) =2316a(19) =2316a(20) =3032a(21) =3128a(22) =3344a(23) =3344a(24) =3692a(25) =3968a(26) =4206a(27) =4206a(28) =4768a(29) =5032