Number of n-celled polyominoes with holes.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =6a(8) =37a(9) =195a(10) =979a(11) =4663a(12) =21474a(13) =96496a(14) =425449a(15) =1849252a(16) =7946380a(17) =33840946a(18) =143060339a(19) =601165888a(20) =2513617990a(21) =10466220315a(22) =43425174374a(23) =179630865835a(24) =741123699012