A137193 Number of n-celled polyhexes with perimeter < 4n+2.

0, 0, 1, 2, 10, 46, 215, 1037, 5083, 24918, 122437

Offset

1,4

Comments

These are n-cell polyhexes with the perimeter less than the maximum possible one.

If we associate a graph to a polyhex with vertices representing cells and edges representing two cells with a common edge, then this sequence enumerates polyhexes whose corresponding graphs have cycles.

Links

Table of n, a(n) for n=1..11.

Formula

A000228(n)-A038142(n)

Crossrefs

Sequence in context: A106709 A204091 A221196 * A006213 A137635 A029706

Adjacent sequences: A137190 A137191 A137192 * A137194 A137195 A137196

Keyword

hard,more,nonn

Author

Tanya Khovanova, Mar 03 2008

Status

approved