A244972 Orders of primitive groups not synchronizing a rank 3 map.

3, 9, 21, 27, 45, 81, 153, 243, 441, 495, 729

Offset: 1

Author

Peter J. Cameron, Nov 12 2014

Keywords

• nonn
• hard
• more

Comments

Also, orders of graphs with clique number and chromatic number 3 which have primitive automorphism groups.

Examples

			The graphs on 3^n vertices are the Hamming graphs over 3-letter alphabet; the graphs with 21, 45 and 153 vertices are the line graphs of the 6-cage, 8-cage, and Biggs-Smith graph respectively.