Partial sums of A051947.

Terms

a(0) =1a(1) =11a(2) =60a(3) =228a(4) =690a(5) =1782a(6) =4092a(7) =8580a(8) =16731a(9) =30745a(10) =53768a(11) =90168a(12) =145860a(13) =228684a(14) =348840a(15) =519384a(16) =756789a(17) =1081575a(18) =1519012a(19) =2099900a(20) =2861430a(21) =3848130a(22) =5112900a(23) =6718140a(24) =8736975a(25) =11254581a(26) =14369616a(27) =18195760a(28) =22863368a(29) =28521240