The Wiener index of the linear phenylene with n hexagons.

Terms

a(0) =27a(1) =180a(2) =567a(3) =1296a(4) =2475a(5) =4212a(6) =6615a(7) =9792a(8) =13851a(9) =18900a(10) =25047a(11) =32400a(12) =41067a(13) =51156a(14) =62775a(15) =76032a(16) =91035a(17) =107892a(18) =126711a(19) =147600a(20) =170667a(21) =196020a(22) =223767a(23) =254016a(24) =286875a(25) =322452a(26) =360855a(27) =402192a(28) =446571a(29) =494100