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%I #31 Dec 29 2018 03:27:24
%S 1,3,4,6,9,11,14,18,21,25
%N Consider a triangular Go board graph with side length n; remove i nodes and let j be the number of nodes in the largest connected subgraph remaining; then a(n) = minimum (i + j).
%C Maximum number of boat shapes formed from six equilateral triangles that can be placed in an equilateral triangle of order a(n+4). - _Craig Knecht_, Sep 13 2017
%H Gordon Hamilton, <a href="http://youtu.be/dxnxRmVPjFk">Children working on this problem in grade 2 classrooms</a>
%H Craig Knecht, <a href="/A243302/a243302.png">Maximum number of six triangle boat shapes in a equilateral triangle.</a>
%e a(11) <= 29 because i = 20 and j = 9 in the following graph:
%e -
%e - -
%e - - -
%e X - - X
%e - X - X -
%e - - X X - -
%e - - X - X - -
%e X X X - - X X X
%e - - - X - X - - -
%e - - - X - - X - - -
%e - - - X - - - X - - -
%e a(11) <= 29 because i = 16 and j = 13 in the following graph:
%e -
%e - -
%e - - -
%e - - - -
%e X X - - -
%e - - X X X X
%e - - X - X - -
%e - - X - - X - -
%e - - X - - - X - -
%e - - X - - - X - - -
%e - - X - - - X - - - -
%Y For square graphs see A243205.
%Y Cf. A301654.
%K nonn,more
%O 1,2
%A _Gordon Hamilton_, Jun 03 2014