Partial sums of A051865.

Terms

a(0) =0a(1) =1a(2) =14a(3) =50a(4) =120a(5) =235a(6) =406a(7) =644a(8) =960a(9) =1365a(10) =1870a(11) =2486a(12) =3224a(13) =4095a(14) =5110a(15) =6280a(16) =7616a(17) =9129a(18) =10830a(19) =12730a(20) =14840a(21) =17171a(22) =19734a(23) =22540a(24) =25600a(25) =28925a(26) =32526a(27) =36414a(28) =40600a(29) =45095