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%I #17 Dec 20 2019 14:52:43
%S 6,21,26,81,129,349,650,1614,3281,7772,16565,38265,83635,190656,
%T 422266,955967,2131986,4809229,10764221,24235939,54347662,122246248,
%U 274396853,616899656,1385407029
%N Number of strong elementary edge-subgraphs in Moebius ladder M_n.
%H J. P. McSorley, <a href="http://dx.doi.org/10.1016/S0012-365X(97)00086-1">Counting structures in the Moebius ladder</a>, Discrete Math., 184 (1998), 137-164.
%F Conjectures from _Colin Barker_, Dec 20 2019: (Start)
%F G.f.: x^2*(6 + 9*x - 46*x^2 - 22*x^3 + 74*x^4 + 16*x^5 - 38*x^6 - 3*x^7 + 6*x^8) / ((1 - x)*(1 + x)*(1 + x - x^2)*(1 - x - x^2)*(1 - 2*x - x^2 + x^3)).
%F a(n) = 2*a(n-1) + 5*a(n-2) - 9*a(n-3) - 8*a(n-4) + 12*a(n-5) + 5*a(n-6) - 6*a(n-7) - a(n-8) + a(n-9) for n>10.
%F (End)
%K nonn,more
%O 2,1
%A _N. J. A. Sloane_
%E a(6)-a(26) from _Sean A. Irvine_, May 01 2019
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