Number of polyiamonds with n cells that do not tile the plane.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =0a(8) =21a(9) =107a(10) =619a(11) =1300a(12) =6740a(13) =19812a(14) =61075a(15) =181036a(16) =577551a(17) =1626183a(18) =4904626a(19) =14071461a(20) =41336066a(21) =120630534a(22) =352200161a(23) =1023454347a(24) =2997105957a(25) =8761810505a(26) =25648786717a(27) =75161609591a(28) =220583137840a(29) =647825855933