Number of 2 X 2 planar subsets in an n X n X n cube.

Terms

a(0) =0a(1) =0a(2) =6a(3) =36a(4) =108a(5) =240a(6) =450a(7) =756a(8) =1176a(9) =1728a(10) =2430a(11) =3300a(12) =4356a(13) =5616a(14) =7098a(15) =8820a(16) =10800a(17) =13056a(18) =15606a(19) =18468a(20) =21660a(21) =25200a(22) =29106a(23) =33396a(24) =38088a(25) =43200a(26) =48750a(27) =54756a(28) =61236a(29) =68208