A122687 Irregular triangle read by rows giving numbers of azulenoid isomers (see Brunvoll et al. for precise definition).

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

Offset

1,6

References

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

Links

Table of n, a(n) for n=1..24.

Example

Triangle begins:
0
1
1 1
1 2 2
4 3 3 1
4 7 9 2 3 0
18 14 13 10 7 1 1

Crossrefs

Sequence in context: A248345 A094953 A332862 * A002948 A117113 A239430

Adjacent sequences: A122684 A122685 A122686 * A122688 A122689 A122690

Keyword

nonn,tabf

Author

N. J. A. Sloane, Sep 23 2006

Status

approved