%I #9 Jan 01 2019 15:18:08
%S 1,0,1,0,1,2,1,1,1,1,3,1,1,1,1,3,1,1,1,1,3,1,1,1,1,3,1,1,1,1,3,1,1,1,
%T 1,3,1,1,1,1,3,1,1,1,1,3,1,1,1,1,3,1,1,1,1,3,1,1,1,1,3,1,1,1,1,3,1,1,
%U 1,1,3,1,1,1,1,3,1,1,1,1,3,1,1,1,1,3,1,1,1,1
%N Number of nonisomorphic generalized Petersen graphs P(n,k) with girth 5 on 2n vertices for 1<=k<=Floor[(n-1)/2].
%C The generalized Petersen graph P(n,k) is a graph with vertex set V(P(n,k)) = {u_0,u_1,...,u_{n-1},v_0,v_1,...,v_{n-1}} and edge set E(P(n,k)) = {u_i u_{i+1}, u_i v_i, v_i v_{i+k} : i=0,...,n-1}, where the subscripts are to be read modulo n.
%D I. Z. Bouwer, W. W. Chernoff, B. Monson and Z. Star, The Foster Census (Charles Babbage Research Centre, 1988), ISBN 0-919611-19-2.
%H Marko Boben, Tomaz Pisanski, Arjana Zitnik, <a href="http://preprinti.imfm.si/PDF/00939.pdf">I-graphs and the corresponding configurations</a>, Preprint series (University of Ljubljana, IMFM), Vol. 42 (2004), 939 (ISSN 1318-4865).
%H M. Watkins, <a href="https://doi.org/10.1016/S0021-9800(69)80116-X">A theorem on Tait colorings with an application to the generalized Petersen graphs</a>, J. Combin. Theory 6 (1969), 152-164.
%e A generalized Petersen graph P(n,k) has girth 5 if and only if it has girth more than 4 and (n=5k or 2n=5k or k=2 or 2k=n-1).
%e The smallest generalized Petersen graph with girth 5 is P(5,2)
%Y Cf. A077105, A107452-A107460.
%K nonn
%O 5,6
%A Marko Boben (Marko.Boben(AT)fmf.uni-lj.si), _Tomaz Pisanski_ and Arjana Zitnik (Arjana.Zitnik(AT)fmf.uni-lj.si), May 26 2005