Number of n-celled polytans with holes.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =2a(7) =11a(8) =76a(9) =422a(10) =2187a(11) =10625a(12) =49381a(13) =221738a(14) =969583a(15) =4153567