Number of right triangles whose vertices are lattice points in {1,2,...,n} X {1,2,...,n}.

Terms

a(0) =0a(1) =4a(2) =44a(3) =200a(4) =596a(5) =1444a(6) =2960a(7) =5520a(8) =9496a(9) =15332a(10) =23596a(11) =34936a(12) =50020a(13) =69732a(14) =94816a(15) =126176a(16) =164960a(17) =212372a(18) =269620a(19) =337960a(20) =418716a(21) =513444a(22) =623736a(23) =751152a(24) =897776a(25) =1065220a(26) =1255460a(27) =1470680a(28) =1713052a(29) =1984564