This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A123353 #12 Feb 24 2025 08:52:49 %S A123353 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 A123353 1,1,7,196,3136,15218,11957,704,1,1,8,336,9996,118188,326053,114972, %U A123353 2431,1,1,9,540,27468,690480,5355756,7736092,1157650,8502,1 %N A123353 Triangle read by rows, giving Kekulé numbers for certain benzenoids (see the Cyvin-Gutman book for details). %D A123353 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 A123353 Triangle begins: %e A123353 1 %e A123353 1 1 %e A123353 1 2 1 %e A123353 1 3 6 1 %e A123353 1 4 20 19 1 %e A123353 1 5 50 155 62 1 %e A123353 1 6 105 805 1315 207 1 %e A123353 1 7 196 3136 15218 11957 704 1 %e A123353 1 8 336 9996 118188 326053 114972 2431 1 %e A123353 1 9 540 27468 690480 5355756 7736092 1157650 8502 1 %e A123353 1 10 825 67320 3256308 60864012 282497568 199806100 12115220 30056 1 %Y A123353 Diagonals give A026012, A123355, A123356. %K A123353 nonn,tabl %O A123353 0,5 %A A123353 _N. J. A. Sloane_, Oct 14 2006