Coordination sequence for C_4 lattice.

Terms

a(0) =1a(1) =32a(2) =192a(3) =608a(4) =1408a(5) =2720a(6) =4672a(7) =7392a(8) =11008a(9) =15648a(10) =21440a(11) =28512a(12) =36992a(13) =47008a(14) =58688a(15) =72160a(16) =87552a(17) =104992a(18) =124608a(19) =146528a(20) =170880a(21) =197792a(22) =227392a(23) =259808a(24) =295168a(25) =333600a(26) =375232a(27) =420192a(28) =468608