Detour index of the n X n grid graph.

Terms

a(0) =0a(1) =16a(2) =256a(3) =1744a(4) =6912a(5) =21744a(6) =55296a(7) =126016a(8) =256000a(9) =487600a(10) =864000a(11) =1467216a(12) =2370816a(13) =3716944a(14) =5619712a(15) =8306944a(16) =11943936a(17) =16875216a(18) =23328000a(19) =31800400a(20) =42592000a(21) =56397616a(22) =73598976a(23) =95137344a(24) =121485312a(25) =153887344a(26) =192914176a(27) =240177616a(28) =296352000a(29) =363488400