Number of symmetric types of (4,2n)-hypergraphs under action of complementing group C(4,2).

Terms

a(0) =1a(1) =15a(2) =50a(3) =225a(4) =590a(5) =1485a(6) =3130a(7) =6435a(8) =11931a(9) =21450a(10) =36220a(11) =59670a(12) =94140a(13) =145350a(14) =217500a(15) =319770a(16) =458981a(17) =648945a(18) =900350a(19) =1233375a(20) =1663850a(21) =2220075a(22) =2924870a(23) =3817125a(24) =4928511a(25) =6310980a(26) =8007640a(27) =10086780a(28) =12605560a(29) =15651900