Number of 4-cycles in the n-halved cube graph.

Terms

a(0) =0a(1) =0a(2) =3a(3) =102a(4) =900a(5) =5160a(6) =23520a(7) =92736a(8) =330624a(9) =1094400a(10) =3421440a(11) =10222080a(12) =29432832a(13) =82188288a(14) =223641600a(15) =595230720a(16) =1554186240a(17) =3990749184a(18) =10097197056a(19) =25214976000a(20) =62234296320a(21) =151993712640a(22) =367691563008a(23) =881823055872