The hyper-Wiener index of the hexagonal triangle T_n, defined in the He et al. reference.

Terms

a(0) =0a(1) =42a(2) =444a(3) =2187a(4) =7443a(5) =20247a(6) =47313a(7) =98994a(8) =190386a(9) =342576a(10) =584034a(11) =952149a(12) =1494909a(13) =2272725a(14) =3360399a(15) =4849236a(16) =6849300a(17) =9491814a(18) =12931704a(19) =17350287a(20) =22958103a(21) =29997891a(22) =38747709a(23) =49524198a(24) =62685990a(25) =78637260a(26) =97831422a(27) =120774969a(28) =148031457a(29) =180225633