Number of rounded n-celled polyominoes.

Terms

a(0) =1a(1) =2a(2) =5a(3) =22a(4) =99a(5) =580a(6) =3557a(7) =23295a(8) =155437a(9) =1057516a(10) =7271980a(11) =50478035a(12) =352901040