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Number of staircase polygons of area n with 3 (staircase polygon) holes on square lattice (not allowing rotations).
1

%I #11 Jul 19 2014 09:30:16

%S 4,30,184,894,3885,15386,56956,199620,669702,2166462,6798186,20786496,

%T 62160079,182336358,525931258,1494726848,4192885357,11625457180,

%U 31899800729,86717361496,233754981005,625311996048

%N Number of staircase polygons of area n with 3 (staircase polygon) holes on square lattice (not allowing rotations).

%H I. Jensen, <a href="/A057416/b057416.txt">Table of n, a(n) for n = 18..89</a> (from link below)

%H I. Jensen, <a href="http://www.ms.unimelb.edu.au/~iwan/polygons/series/staircase.area.3hole.ser">More terms</a>

%K nonn

%O 18,1

%A _N. J. A. Sloane_, Aug 30 2000