Degree-diameter problem $N(6,2)$

The largest possible number of vertices in a graph of maximum degree $6$ and diameter $2$.

Updates

• 1977 Lower bound: $32$
  Wegner, G. (1977). Graphs with given diameter and a coloring problem.
  [via Table of the largest known graphs of a given diameter and maximal degree - Wikipedia]
• 2006 Upper bound: $32$
  Molodtsov, S. G. (2006). Largest graphs of diameter 2 and maximum degree 6. General Theory of Information Transfer and Combinatorics, 853-857.
  [via Table of the largest known graphs of a given diameter and maximal degree - Wikipedia]