A123353 Triangle read by rows, giving Kekulé numbers for certain benzenoids (see the Cyvin-Gutman book for details).

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, 1

Offset

0,5

References

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

Links

Table of n, a(n) for n=0..27.

Example

Triangle begins:
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 1

Crossrefs

Diagonals give A026012, A123355, A123356.

Sequence in context: A107702 A174480 A111670 * A156540 A156582 A156953

Adjacent sequences: A123350 A123351 A123352 * A123354 A123355 A123356

Keyword

nonn,tabl,more

Author

N. J. A. Sloane, Oct 14 2006

Status

approved