Floor(AGM(n^2, n^3)), where AGM denotes the arithmetic-geometric mean.

Terms

a(0) =0a(1) =1a(2) =5a(3) =16a(4) =35a(5) =65a(6) =106a(7) =161a(8) =231a(9) =318a(10) =425a(11) =551a(12) =700a(13) =872a(14) =1069a(15) =1293a(16) =1545a(17) =1827a(18) =2140a(19) =2486a(20) =2866a(21) =3281a(22) =3734a(23) =4225a(24) =4755a(25) =5327a(26) =5942a(27) =6601a(28) =7306a(29) =8057