Crystal ball sequence for the lattice C_4.

Terms

a(0) =1a(1) =33a(2) =225a(3) =833a(4) =2241a(5) =4961a(6) =9633a(7) =17025a(8) =28033a(9) =43681a(10) =65121a(11) =93633a(12) =130625a(13) =177633a(14) =236321a(15) =308481a(16) =396033a(17) =501025a(18) =625633a(19) =772161a(20) =943041a(21) =1140833a(22) =1368225a(23) =1628033a(24) =1923201a(25) =2256801a(26) =2632033a(27) =3052225a(28) =3520833a(29) =4041441