%N Consider the tiling of the plane with squares of two different sizes as in Fig. 2.4.2(g) of Grünbaum and Shephard, p. 74. a(n) is the number of connected figures that can be formed on this tiling, from n tiles, each composed of a big square and an adjacent little square.
%C The Zucca web site calls these figures "n-PairSquares".
%D Branko Grünbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987.
%H Livio Zucca, <a href="http://www.iread.it/lz/polymultiforms2.html">PolyMultiForms</a>
%Y Cf. A121195, A121197, A121198.
%A _N. J. A. Sloane_, Aug 17 2006
%E Better definition from _Don Reble_, Aug 17 2007