A126738 - OEIS

%I #9 Aug 15 2019 16:51:08

%S 0,0,0,1,3,26,282,5009,149551,7694428,667036310

%N Number of connected graphs on n nodes with chromatic number 4.

%H Keith M. Briggs, <a href="http://keithbriggs.info/cgt.html">Combinatorial Graph Theory</a>

%Y A diagonal of triangle in A126736.

%K nonn

%O 1,5

%A _N. J. A. Sloane_, Feb 16 2007

%E a(11) from _Michael Sollami_, Jan 29 2012