Szeged index of the grid graph P_n X P_n.

Terms

a(0) =0a(1) =16a(2) =216a(3) =1280a(4) =5000a(5) =15120a(6) =38416a(7) =86016a(8) =174960a(9) =330000a(10) =585640a(11) =988416a(12) =1599416a(13) =2497040a(14) =3780000a(15) =5570560a(16) =8018016a(17) =11302416a(18) =15638520a(19) =21280000a(20) =28523880a(21) =37715216a(22) =49252016a(23) =63590400a(24) =81250000a(25) =102819600a(26) =128963016a(27) =160425216a(28) =198038680a(29) =242730000