%I A057409
%S A057409 1,2,6,19,63,216,756,2685,9650,35018,128084,471623,1746492,6499356,
%T A057409 24290272,91123171,342984175,1294829776,4901319978,18597856445,
%U A057409 70723784744,269486503694,1028736811230,3933715966653
%N A057409 Number of self-avoiding polygons of area n with any number of (self-avoiding 
               polygon) holes on square lattice (not allowing rotations).
%H A057409 I. Jensen, <a href="b057409.txt">Table of n, a(n) for n = 1..40</a> (from 
               link below)
%H A057409 I. Jensen, <a href="http://www.ms.unimelb.edu.au/~iwan/polygons/series/
               square.area.allholes.ser">More terms</a>
%Y A057409 Sequence in context: A059713 A109262 A006724 this_sequence A141771 A001170 
               A001168
%Y A057409 Adjacent sequences: A057406 A057407 A057408 this_sequence A057410 A057411 
               A057412
%K A057409 nonn
%O A057409 1,2
%A A057409 N. J. A. Sloane (njas(AT)research.att.com), Aug 30 2000