Partial sums of A050484.

Terms

a(0) =1a(1) =13a(2) =81a(3) =345a(4) =1155a(5) =3267a(6) =8151a(7) =18447a(8) =38610a(9) =75790a(10) =140998a(11) =250614a(12) =428298a(13) =707370a(14) =1133730a(15) =1769394a(16) =2696727a(17) =4023459a(18) =5888575a(19) =8469175a(20) =11988405a(21) =16724565a(22) =23021505a(23) =31300425a(24) =42073200a(25) =55957356a(26) =73692828a(27) =96160636a(28) =124403620a(29) =159649380