%I A020876
%S A020876 2,5,15,50,175,625,2250,8125,29375,106250,384375,1390625,
%T A020876 5031250,18203125,65859375,238281250,862109375,3119140625,
%U A020876 11285156250,40830078125,147724609375,534472656250,1933740234375
%N A020876 Number of no-leaf edge-subgraphs in Moebius ladder M_n.
%D A020876 J. P. McSorley, Counting structures in the Moebius ladder, Discrete Math., 
               184 (1998), 137-164.
%F A020876 ((5+sqrt(5))/2)^n+((5-sqrt(5))/2)^n.
%F A020876 Let S(n, m)=sum(k=0, n, binomial(n, k)*fibonacci(m*k)), then for n>0 
               a(n)=S(2*n, 2)/S(n, 2) - Benoit Cloitre (benoit7848c(AT)orange.fr), 
               Oct 22 2003
%o A020876 sage: [lucas_number2(n,5,5) for n in xrange(0,24)] - Zerinvary Lajos 
               (zerinvarylajos(AT)yahoo.com), Jul 08 2008
%Y A020876 Sequence in context: A149946 A149947 A149948 this_sequence A093129 A149949 
               A149950
%Y A020876 Adjacent sequences: A020873 A020874 A020875 this_sequence A020877 A020878 
               A020879
%K A020876 nonn
%O A020876 0,1
%A A020876 N. J. A. Sloane (njas(AT)research.att.com).