A row-convex polyomino is a self-avoiding convex polyomino such that the intersection of any horizontal line with the polyomino
has at most two connected components. A row-convex polyomino is also called a horizontally
convex polyomino. Klarner (1965) gave an explicit expression for the generating
function of row-convex polyominoes enumerated according to area.
Delest, M.-P. and Viennot, G. "Algebraic Language and Polyominoes [sic] Enumerations." Theor. Comput. Sci.34, 169-206,
1984.Klarner, D. "Some Results Concerning Polyominoes." Fib.
Quart.3, 9-20, 1965.
