Partial sums of A011757.

Terms

a(0) =2a(1) =9a(2) =32a(3) =85a(4) =182a(5) =333a(6) =560a(7) =871a(8) =1290a(9) =1831a(10) =2492a(11) =3319a(12) =4328a(13) =5521a(14) =6948a(15) =8567a(16) =10446a(17) =12589a(18) =15026a(19) =17767a(20) =20850a(21) =24311a(22) =28114a(23) =32325a(24) =36962a(25) =42013a(26) =47532a(27) =53539a(28) =60020a(29) =67017