Partial sums of A053296.

Terms

a(0) =1a(1) =9a(2) =46a(3) =175a(4) =551a(5) =1518a(6) =3785a(7) =8735a(8) =18955a(9) =39130a(10) =77533a(11) =148487a(12) =276408a(13) =502415a(14) =895103a(15) =1568062a(16) =2708322a(17) =4622488a(18) =7811510a(19) =13091798a(20) =21791338a(21) =36067176a(22) =59419294a(23) =97522270a(24) =159571139a(25) =260459265a(26) =424302452a(27) =690141333