Column 9 of triangle A055907.

Terms

a(0) =1a(1) =18a(2) =164a(3) =1050a(4) =5367a(5) =23232a(6) =88125a(7) =299992a(8) =932849a(9) =2685747a(10) =7235237a(11) =18392853a(12) =44427807a(13) =102552852a(14) =227298680a(15) =485679518a(16) =1003915611a(17) =2013360324a(18) =3927664296a(19) =7469755903a(20) =13876848040a(21) =25225619858a(22) =44939663514a(23) =78569415198a(24) =134974052794a(25) =228088973049