

A177921


Number of ovalpartitions of the regular 2ngon {2n}.


1




OFFSET

1,3


COMMENTS

For each n there is a list of floor(n/2) rhombs, a four sided parallelogram with principal index a number from {1, 2, ..., floor(n/2)}. Such rhombs can tile an (n, k)oval. An (n, k)oval is a centrosymmetric polygon with 2k sides and contains k(k1)/2 rhombs. The regular 2ngon {2n} with 2n sides is an (n,n)oval. Its rhombs can be partitioned into (n, k)ovals for various values of k. This partition is called an ovalpartition of {2n}. Here, a(n) is the number of ovalpartitions of {2n}.


LINKS

Table of n, a(n) for n=1..6.
John P. McSorley and Alan H. Schoen, Rhombic tilings of (n, k)ovals, (n, k, lambda)cyclic difference sets, and related topics, Discrete Math., 313 (2013), 129154.  From N. J. A. Sloane, Nov 26 2012
A. H. Schoen, See ROMBIX Supplementary Manual 1994


CROSSREFS

Sequence A181148 gives the total number of distinct ovalpartitions of {2n}.
Sequence in context: A020106 A099928 A000568 * A301481 A128648 A128646
Adjacent sequences: A177918 A177919 A177920 * A177922 A177923 A177924


KEYWORD

nonn,more


AUTHOR

John P. McSorley, Dec 15 2010


EXTENSIONS

Website reference updated by John P. McSorley


STATUS

approved



