Bond percolation series for hexagonal lattice.

Terms

a(0) =1a(1) =3a(2) =9a(3) =25a(4) =66a(5) =168a(6) =417a(7) =1014a(8) =2427a(9) =5737a(10) =13412a(11) =31088a(12) =71506a(13) =163378a(14) =371272a(15) =839248a(16) =1889019a(17) =4235082a(18) =9459687a(19) =21067566a(20) =46769977a(21) =103574916a(22) =228808544a(23) =504286803a(24) =1109344029a(25) =2435398781a(26) =5337497418a(27) =11678931098