Number of non-isomorphic cross-balanced multiset partitions of weight n.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =11a(5) =26a(6) =77a(7) =220a(8) =677a(9) =2098a(10) =6756a(11) =22101a(12) =74264a(13) =253684a(14) =883795a(15) =3130432a(16) =11275246a(17) =41240180a(18) =153117873a(19) =576634463a(20) =2201600769a(21) =8517634249a(22) =33378499157a(23) =132438117118a(24) =531873247805