%I #13 Apr 26 2022 20:55:01
%S 4,12,48,188,740,2936,11672,46388,184352,732608,2911040,11565964,
%T 45949600,182538264,725108640,2880270032,11440564516,45441048384,
%U 180483666608,716832688844,2847012624636,11307166941460
%N a(n) is the total perimeter of all self-avoiding polygons of area n on the square lattice.
%H I. Jensen, <a href="/A056632/b056632.txt">Table of n, a(n) for n = 1..40</a> (from link below)
%H I. Jensen, <a href="http://www.ms.unimelb.edu.au/~iwan/polygons/series/square.peri_mom1.ser">More terms</a>
%Y Cf. A002931, A056625.
%K nonn
%O 1,1
%A _N. J. A. Sloane_, Aug 30 2000
%E Title clarified by _Sean A. Irvine_, Apr 26 2022