Number of imperfect staircase polygons by area.

Terms

a(0) =1a(1) =4a(2) =15a(3) =47a(4) =143a(5) =412a(6) =1157a(7) =3170a(8) =8534a(9) =22631a(10) =59295a(11) =153768a(12) =395297a(13) =1008606a(14) =2556663a(15) =6443702a(16) =16158018a(17) =40334613a(18) =100277824a(19) =248396782a(20) =613265776a(21) =1509538293a(22) =3705476893a(23) =9072944868a(24) =22163755695a(25) =54026509101a(26) =131433905615