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%I #17 Mar 25 2015 01:51:08
%S 1,3,5,9,12,16,20,25,29
%N Consider the n X n Go board as a graph; remove i nodes and let j be the number of nodes in the largest connected subgraph remaining; then a(n) = minimum (i + j).
%C I believe the next terms are 36, 41, 47, ...
%H Gordon Hamilton, <a href="http://youtu.be/dxnxRmVPjFk">Termite Terrorists</a>: Children working on this problem in grade 2 classrooms. Published on YouTube.com, Jan 01 2013.
%e a(10) <= 36 because i + j = 18 + 18 = 36 in the left graph and i + j = 23 + 13 = 36 in the right graph. 36 may be the minimum.
%e -----X---- -----X----
%e ----X----- -----X----
%e ---X-X---- ---XX-X---
%e --X---X--- XXX----X--
%e -X-----X-X ---X----XX
%e X-X-----X- ----X--X--
%e ---X---X-- ---X-X-X--
%e ----X-X--- --X---X---
%e -----X---- -X----X---
%e ----X----- X-----X---
%K more,nonn
%O 1,2
%A _Gordon Hamilton_, Jun 01 2014
%E Edited by _N. J. A. Sloane_, Jun 02 2014
%E Minor edits by _M. F. Hasler_, Mar 21 2015