Number of different deltoids (including squares) whose vertices are on an n X n grid.

Terms

a(0) =0a(1) =1a(2) =4a(3) =11a(4) =26a(5) =46a(6) =84a(7) =123a(8) =194a(9) =268a(10) =378a(11) =478a(12) =657a(13) =800a(14) =1019a(15) =1239a(16) =1548a(17) =1793a(18) =2197a(19) =2505a(20) =3003a(21) =3434a(22) =3991a(23) =4444a(24) =5223a(25) =5801a(26) =6582a(27) =7292a(28) =8274a(29) =9006