Number of horizontally convex n-ominoes in which the top row has exactly 1 square, which is not above the rightmost square in the second row.

A049221

Number of horizontally convex n-ominoes in which the top row has exactly 1 square, which is not above the rightmost square in the second row.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =4a(4) =14a(5) =46a(6) =148a(7) =474a(8) =1518a(9) =4864a(10) =15590a(11) =49974a(12) =160196a(13) =513522a(14) =1646134a(15) =5276800a(16) =16915150a(17) =54222686a(18) =173814580a(19) =557174698a(20) =1786062174a(21) =5725346304a(22) =18352995094a(23) =58831800038a(24) =188589419748a(25) =604536478850

External references