A057412 - OEIS

%I #6 Mar 30 2012 16:48:52

%S 28,884,15266,191688,1964414,17460336,139630696,1029053248,7106319403,

%T 46539551768,291656481886,1761110727936,10301848134999,58631700564776,

%U 325806962400428,1772760905500304,9467673927142781

%N Number of staircase polygons of perimeter 2n with 3 (staircase polygon) holes on square lattice (not allowing rotations).

%H I. Jensen, <a href="/A057412/b057412.txt">Table of n, a(n) for n = 16..67</a> (from link below)

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

%K nonn

%O 16,1

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