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%I #15 Aug 13 2020 14:02:28
%S 0,1,2,3,4,6,8,11,14,18,21,25,30,35,40
%N Minimal number of V-trominoes needed to prevent any further V-trominoe from being placed on an n X n grid.
%C The V-trominoes must line up with the squares on the grid (skew placements are not allowed).
%C a(n) is the independent domination number of a graph with one node per tromino and an edge for each pair of trominoes that conflict. - _Rob Pratt_, Oct 02 2019
%H Juris Cernenoks, <a href="/A238381/a238381.png">Illustration of initial terms</a>
%H Erich Friedman, <a href="https://erich-friedman.github.io/mathmagic/0600.html">Problem of the Month (June 2000)</a>
%Y Cf. A226918.
%K nonn,more
%O 1,3
%A _Juris Cernenoks_, Feb 25 2014
%E a(13)-a(15) from _Rob Pratt_, Oct 02 2019