A123353 - OEIS

%I #12 Feb 24 2025 08:52:49

%S 1,1,1,1,2,1,1,3,6,1,1,4,20,19,1,1,5,50,155,62,1,1,6,105,805,1315,207,

%T 1,1,7,196,3136,15218,11957,704,1,1,8,336,9996,118188,326053,114972,

%U 2431,1,1,9,540,27468,690480,5355756,7736092,1157650,8502,1

%N Triangle read by rows, giving Kekulé numbers for certain benzenoids (see the Cyvin-Gutman book for details).

%D S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (see p. 188).

%e Triangle begins:

%e   1

%e   1 1

%e   1 2 1

%e   1 3 6 1

%e   1 4 20 19 1

%e   1 5 50 155 62 1

%e   1 6 105 805 1315 207 1

%e   1 7 196 3136 15218 11957 704 1

%e   1 8 336 9996 118188 326053 114972 2431 1

%e   1 9 540 27468 690480 5355756 7736092 1157650 8502 1

%e   1 10 825 67320 3256308 60864012 282497568 199806100 12115220 30056 1

%Y Diagonals give A026012, A123355, A123356.

%K nonn,tabl,changed

%O 0,5

%A _N. J. A. Sloane_, Oct 14 2006