Lower (1/2,1/3) midsequence of (n^2) and (n^3); see Comments.

Terms

a(0) =0a(1) =0a(2) =4a(3) =13a(4) =29a(5) =54a(6) =90a(7) =138a(8) =202a(9) =283a(10) =383a(11) =504a(12) =648a(13) =816a(14) =1012a(15) =1237a(16) =1493a(17) =1782a(18) =2106a(19) =2466a(20) =2866a(21) =3307a(22) =3791a(23) =4320a(24) =4896a(25) =5520a(26) =6196a(27) =6925a(28) =7709a(29) =8550