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Number of induced cycles in the 5 X n grid graph.
2

%I #11 Feb 23 2023 13:21:39

%S 0,4,14,58,229,749,2180,6188,17912,52620,154383,450195,1309452,

%T 3811888,11110432,32392550,94412963,275116777,801676752,2336222946,

%U 6808405238,19841419978,57821971765,168504312515,491055599116,1431039769316,4170353383134,12153282490316,35417189532323

%N Number of induced cycles in the 5 X n grid graph.

%H Andrew Howroyd, <a href="/A360198/b360198.txt">Table of n, a(n) for n = 1..200</a>

%H <a href="/index/Rec#order_15">Index entries for linear recurrences with constant coefficients</a>, signature (6,-14,17,-3,-17,16,-2,9,-27,5,19,-3,-2,-5,2).

%F G.f.: x^2*(4 - 10*x + 30*x^2 + 9*x^3 - 39*x^4 + 16*x^5 + 49*x^6 + 28*x^7 - 76*x^8 - 58*x^9 + 7*x^10 + 13*x^11 + 9*x^12 - 4*x^13)/((1 - x)^2*(1 - 4*x + 5*x^2 - 3*x^3 - 8*x^4 + 4*x^5 - 2*x^7 - 13*x^8 + 3*x^9 + 14*x^10 + 6*x^11 + x^12 - 2*x^13)).

%Y Row 5 of A360196.

%K nonn,easy

%O 1,2

%A _Andrew Howroyd_, Jan 29 2023

%E Missing a(1)=0 inserted by _Andrew Howroyd_, Feb 23 2023