Number of planar distributive lattices with n nodes.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =5a(6) =8a(7) =14a(8) =24a(9) =42a(10) =72a(11) =127a(12) =221a(13) =390a(14) =684a(15) =1207a(16) =2125a(17) =3753a(18) =6620a(19) =11698a(20) =20659a(21) =36518a(22) =64533a(23) =114099a(24) =201707a(25) =356683a(26) =630693a(27) =1115370a(28) =1972469a(29) =3488489