A197960 - OEIS

%I #5 Mar 30 2012 17:28:44

%S 1,3,7,28,98,432,1846,8455,38764,181840,858387,4093460,19635210,

%T 94757550

%N Number of free poly-IH15-tiles (polydrops) (holes allowed) with n cells.

%D Branko Gruenbaum and G. C. Shephard, Tilings and Patterns. W. H. Freeman, New York, 1987, Sections 6.2 and 9.4.

%H Brendan Owen, <a href="http://web.archive.org/web/20061229103047/http://members.optusnet.com.au/polyforms/2dforms/polydrops/index.htm">Polydrops</a> (gives a(1)-a(10))

%Y Cf. A197958.

%K hard,nonn

%O 1,2

%A _Joseph Myers_, Oct 19 2011