%I #8 Apr 21 2017 20:17:55
%S 1,6,3,36,36,9,216,324,162,27,1296,2592,1944,648,81,7776,19440,19440,
%T 9720,2430,243,46656,139968,174960,116640,43740,8748,729,279936,
%U 979776,1469664,1224720,612360,183708,30618,2187,1679616
%N Triangle whose (i,j)-th entry is binomial(i,j)*6^(i-j)*3^j.
%H B. N. Cyvin et al., <a href="http://match.pmf.kg.ac.rs/electronic_versions/Match34/match34_109-121.pdf">Isomer enumeration of unbranched catacondensed polygonal systems with pentagons and heptagons</a>, Match, No. 34 (Oct 1996), pp. 109-121.
%F G.f.: 1/(1 - 6*x - 3*x*y). - _Ilya Gutkovskiy_, Apr 21 2017
%K nonn,tabl,easy
%O 0,2
%A _N. J. A. Sloane_.