Partial sums of A051923.

Terms

a(0) =1a(1) =10a(2) =52a(3) =192a(4) =570a(5) =1452a(6) =3300a(7) =6864a(8) =13299a(9) =24310a(10) =42328a(11) =70720a(12) =114036a(13) =178296a(14) =271320a(15) =403104a(16) =586245a(17) =836418a(18) =1172908a(19) =1619200a(20) =2203630a(21) =2960100a(22) =3928860a(23) =5157360a(24) =6701175a(25) =8625006a(26) =11003760a(27) =13923712a(28) =17483752a(29) =21796720