Column 2 of A112060.

Terms

a(0) =2a(1) =4a(2) =12a(3) =35a(4) =155a(5) =239a(6) =779a(7) =2855a(8) =5279a(9) =9095a(10) =15695a(11) =59135a(12) =350699a(13) =183395a(14) =1352339a(15) =1477295a(16) =1077959a(17) =6922920a(18) =3038555a(19) =12705840a(20) =14199120