3-coloring in time O(1.3289^n).
R. Beigel
and D. Eppstein.
arXiv:cs.DS/0006046.
J. Algorithms
54:2 (2005) 168-204, doi:10.1016/j.jalgor.2004.06.008.
Journal paper combining 3-coloring algorithms from our FOCS '95 paper with improved bounds from our SODA '01 paper.