Number of planar vertically indecomposable distributive lattices with n nodes.

Terms

a(0) =1a(1) =1a(2) =0a(3) =1a(4) =0a(5) =1a(6) =0a(7) =2a(8) =1a(9) =4a(10) =2a(11) =9a(12) =6a(13) =21a(14) =18a(15) =48a(16) =50a(17) =114a(18) =135a(19) =277a(20) =358a(21) =681a(22) =935a(23) =1693a(24) =2425a(25) =4235a(26) =6258a(27) =10643a(28) =16085a(29) =26852