A121952 Number of isomeric aza-benzenoids with four nitrogen atoms and n hexagons.

3, 22, 194, 1620, 12982, 98765, 720519, 5073805, 34707100, 231739037

Offset

1,1

References

N. Trinajstich, Z. Jericevic, J. V. Knop, W. R. Muller and K. Szymanski, "Computer generation of isomeric structures", Pure and Appl. Chem., vol. 55 (1983) pp. 379-390.

Links

Table of n, a(n) for n=1..10.

Example

If n=5 then the number of isomeric aza-benzenoids with four nitrogen atoms is 12982. Here n is the number of hexagons.

Crossrefs

Sequence in context: A065204 A001393 A046743 * A367393 A250888 A098618

Adjacent sequences: A121949 A121950 A121951 * A121953 A121954 A121955

Keyword

nonn

Author

Parthasarathy Nambi, Sep 04 2006

Status

approved