Number of column-convex polyominoes with perimeter n.

Terms

a(0) =1a(1) =3a(2) =12a(3) =54a(4) =260a(5) =1310a(6) =6821a(7) =36413a(8) =198227a(9) =1096259a(10) =6141764a(11) =34784432a(12) =198828308a(13) =1145544680a(14) =6645621536a(15) =38786564126a(16) =227585926704