%I M3257 #22 Jun 14 2019 21:48:55

%S 0,0,0,4,5,15,21,44,66,120,187,319,507,840,1348,2204,3553,5775,9329,

%T 15124,24454,39600,64055,103679,167735,271440,439176,710644,1149821,

%U 1860495,3010317,4870844,7881162,12752040,20633203,33385279,54018483

%N Number of strict (-1)st-order maximal independent sets in cycle graph.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%D R. Yanco and A. Bagchi, ``K-th order maximal independent sets in path and cycle graphs,'' J. Graph Theory, submitted, 1994.

%H R. Yanco, <a href="/A007380/a007380.pdf">Letter and Email to N. J. A. Sloane, 1994</a>

%F a(n) = A000204(n) - b(n) where b(1) = 1, b(2*n+1) = 2*n+2, b(2*n) = 3. - _Sean A. Irvine_, Jan 02 2018

%F Conjectures from _Colin Barker_, Jun 14 2019: (Start)

%F G.f.: x^4*(4 + x - 2*x^2 - x^3) / ((1 - x)^2*(1 + x)^2*(1 - x - x^2)).

%F a(n) = a(n-1) + 3*a(n-2) - 2*a(n-3) - 3*a(n-4) + a(n-5) + a(n-6) for n>7.

%F (End)

%K nonn

%O 1,4

%A _N. J. A. Sloane_, _Mira Bernstein_

%E a(18) corrected and more terms from _Sean A. Irvine_, Jan 02 2018