%I #16 Dec 20 2019 14:52:35

%S 17,58,181,602,2006,6797,23205,79771,275462,954367,3314074,11526782,

%T 40136519,139865123,487656165,1700907382,5934174209,20707036102,

%U 72265263946,252219473921,880346196329,3072884622527,10726335768378,37442520667627,130702738526702

%N Number of elementary edge-subgraphs in Moebius ladder M_n.

%H Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a020/A020879.java">Java program</a> (github).

%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*(17 - 10*x - 85*x^2 - 51*x^3 + 10*x^4 + 7*x^5) / ((1 + x)*(1 - 2*x - x^2)*(1 - 3*x - 2*x^2 + x^3)).

%F a(n) = 4*a(n-1) + 2*a(n-2) - 11*a(n-3) - 8*a(n-4) + a(n-5) + a(n-6) for n>7.

%F (End)

%K nonn

%O 2,1

%A _N. J. A. Sloane_.

%E a(6)-a(26) from _Sean A. Irvine_, May 01 2019