Sums of knight's moves over the square |i|+|j|<=n on infinite chessboard.

Terms

a(0) =0a(1) =12a(2) =28a(3) =48a(4) =88a(5) =148a(6) =220a(7) =312a(8) =440a(9) =588a(10) =772a(11) =1000a(12) =1248a(13) =1548a(14) =1908a(15) =2288a(16) =2728a(17) =3244a(18) =3788a(19) =4400a(20) =5096a(21) =5828a(22) =6644a(23) =7552a(24) =8496a(25) =9540a(26) =10692a(27) =11880a(28) =13176a(29) =14596