The Lindgren-Sousselier graphs are a sequence of hypohamiltonian graphs with 
vertices independently discovered by Sousselier (in Herz
et al. 1967) and Lindgren (1967) for 
, 2, ..., the first few of which are illustrated above. The
graph with 
is the Petersen graph.
A number of different embeddings of the Lindgren-Sousselier graph on 28 vertices are illustrated above.
The Lindgren-Sousselier graph indexed by 
has graph crossing number
and rectilinear crossing number 
and local crossing number 1. The Lindgren-Sousselier
graphs are therefore nonplanar 1-planar
graphs.
