Number of n-celled polyominoes with perimeter < 2n+2.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =8a(6) =25a(7) =114a(8) =438a(9) =1826a(10) =7339a(11) =29876a(12) =120346a(13) =485155a(14) =1947974a(15) =7812084a(16) =31267765