The Wiener index of the Fibonacci tree of order n.

Terms

a(0) =0a(1) =0a(2) =4a(3) =18a(4) =96a(5) =374a(6) =1380a(7) =4696a(8) =15336a(9) =48318a(10) =148448a(11) =446890a(12) =1324104a(13) =3872656a(14) =11206764a(15) =32143818a(16) =91509120a(17) =258855006a(18) =728211180a(19) =2038815272a(20) =5684262480a(21) =15789141750a(22) =43712852544a(23) =120663667538a(24) =332191809936a(25) =912339490464