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%I #8 Feb 25 2023 20:57:14
%S 3,8,17,32,66,130,262,522,1046,2090,4182,8362,16726,33450,66902,
%T 133802,267606,535210,1070422,2140842,4281686,8563370,17126742,
%U 34253482,68506966,137013930,274027862,548055722,1096111446,2192222890,4384445782,8768891562
%N Number of dominating induced trees in the n-ladder graph P_2_X P_n.
%H Andrew Howroyd, <a href="/A360848/b360848.txt">Table of n, a(n) for n = 1..1000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/LadderGraph.html">Ladder Graph</a>.
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1,2).
%F a(n) = a(n-1) + 2*a(n-2) for n > 4.
%F G.f.: x*(3 + 5*x + 3*x^2 - x^3)/((1 + x)*(1 - 2*x)).
%o (PARI) Vec((3 + 5*x + 3*x^2 - x^3)/((1 + x)*(1 - 2*x)) + O(x^20))
%Y Row 2 of A360846.
%K nonn,easy
%O 1,1
%A _Andrew Howroyd_, Feb 23 2023
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