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A057725
Number of "polyares" of order n (turning over not allowed).
1
1, 4, 16, 77, 351, 1747, 8745, 44724, 230765, 1203567, 6323074, 33444084, 177863517, 950557538, 5101540598
OFFSET
1,2
COMMENTS
An n-are is a shape formed from an n-celled polyomino by removing half of each square cell in such a way that at least half of the original join between cells is retained.
REFERENCES
Enumeration attributed by Andrew Clarke to Brendan Owen.
CROSSREFS
Sequence in context: A260949 A049426 A345889 * A196192 A367261 A364474
KEYWORD
nonn,nice,more
AUTHOR
N. J. A. Sloane, Oct 29 2000
EXTENSIONS
Link updated by William Rex Marshall, Dec 16 2009
a(9)-a(11) from Sean A. Irvine, Jul 02 2022
a(12)-a(15) from John Mason, Mar 19 2023
STATUS
approved