Detour index for the n X n torus grid graph.

Terms

a(0) =288a(1) =1744a(2) =7200a(3) =21744a(4) =56448a(5) =126016a(6) =259200a(7) =487600a(8) =871200a(9) =1467216a(10) =2384928a(11) =3716944a(12) =5644800a(13) =8306944a(14) =11985408a(15) =16875216a(16) =23392800a(17) =31800400a(18) =42688800a(19) =56397616a(20) =73738368a(21) =95137344a(22) =121680000a(23) =153887344a(24) =193179168a(25) =240177616a(26) =296704800a(27) =363488400