A007222 Almost-convex polygons of perimeter 2n on square lattice. (Formerly M5203)

28, 1468, 34680, 535452, 6302296, 61400920, 520788460, 3976323744, 27974148068, 184411212644, 1153389882896, 6908837566500, 39921952365008

Offset

10,1

References

I. G. Enting, A. J. Guttmann, L. B. Richmond and N. C. Wormald, Enumeration of almost-convex polygons on the square lattice, Random Structures Algorithms 3 (1992), 445-461.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=10..22.

Crossrefs

Sequence in context: A366302 A013926 A110696 * A209265 A042515 A042512

Adjacent sequences: A007219 A007220 A007221 * A007223 A007224 A007225

Keyword

nonn

Author

Simon Plouffe

Status

approved