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%I #18 Jan 24 2024 08:00:11
%S 3,4,5,8,13,16,18,20,27,32,39,42,45,56,65,72,76,80,95
%N Lower independence number of the n X n torus grid graph C_n square C_n.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/LowerIndependenceNumber.html">Lower Independence Number</a>.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TorusGridGraph.html">Torus Grid Graph</a>.
%t (* conjectured to hold for larger n *)
%t Table[Piecewise[{
%t {n^2/5, Mod[n, 5] == 0},
%t {(n + 4) (n - 2)/5, Mod[n, 5] == 1},
%t {(n + 8) (2 n^2 + 17 n + 108)/375, Mod[n, 5] == 2},
%t {n (n + 2)/5, Mod[n, 5] == 3},
%t {n (n + 1)/5, Mod[n, 5] == 4}
%t }], {n, 3, 21}]
%K nonn,more,hard
%O 3,1
%A _Eric W. Weisstein_, Jan 06 2024
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