A122687 - OEIS

%I #3 Mar 30 2012 16:50:31

%S 0,1,1,1,1,2,2,4,3,3,1,4,7,9,2,3,0,18,14,13,10,7,1,1

%N Irregular triangle read by rows giving numbers of azulenoid isomers (see Brunvoll et al. for precise definition).

%D J. Brunvoll, S. J. Cyvin and B. N. Cyvin, Azulenoids, MATCH, No. 34, 1996, 91-108.

%e Triangle begins:

%e 0

%e 1

%e 1 1

%e 1 2 2

%e 4 3 3 1

%e 4 7 9 2 3 0

%e 18 14 13 10 7 1 1

%K nonn,tabf

%O 1,6

%A _N. J. A. Sloane_, Sep 23 2006