EntityQ5504427· pop 7· linked from 18 articlesfriendship graphSign in to saveplanar undirected graph with 2n+1 vertices and 3n edgesConnectionsmathematicsEntitydigital object identifierEntityPaul ErdősEntitygraph theoryEntitygraphEntityJSTOROrganizationcardinalityEntityMathWorldEntitynodeEntityplanar graphEntitygraph coloringEntityAlfréd RényiEntityEulerian pathEntityEric W. WeissteinEntitygraph isomorphismEntitycycle graphEntityMathematical ReviewsEntityCiteSeerXEntityVera T. SósEntityglossary of graph theory termsEntityCategoriesParametric families of graphsPlanar graphs