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A057787
Number of polyarcs with n cells.
6
2, 7, 22, 93, 364, 1734, 8246, 41043, 206602, 1056831, 5454954, 28394727, 148805868, 784390909
OFFSET
1,1
COMMENTS
Draw a quarter circle with radius one, centered at the corner of a unit square. It divides the square into two pieces. Call these pieces monarcs. Polyarcs are the figures created by joining monarcs edge-to-edge. - Henri Picciotto, Jan 04 2015
Henri Picciotto invented and named the polyarcs in the late 1980’s. They were first published in World Games Review, Michael Keller’s zine. Brendan Owen found and counted the polyarcs to n = 9. - N. J. A. Sloane, Mar 29 2015
When a complete square is present, the internal details of the division (which can happen in four ways) are ignored for the purposes of this sequence. - Sean A. Irvine, Jul 04 2022
LINKS
Michael Keller, Diarcs and Triarcs, World Games Review 'Zine (#9, Dec 1989). [Illustration of a(3)=22]
Michael Keller, Diarcs and Triarcs [Illustration of a(3)=22] [Cached copy in pdf format]
Brendan Owen, Tetrarcs and Pentarcs [Illustration of a(4)=93, a(5)=364]
Brendan Owen, Tetrarcs and Pentarcs [Illustration of a(4)=93, a(5)=364] [Cached copy in pdf format]
Henri Picciotto's Math Education Page, Polyarcs, in Geometric Puzzles in the Classroom. Also contains other polyarc links.
Henri Picciotto, Illustration of definition, a(1)=2 and a(2)=7. [A brief section from Geometric Puzzles in the Classroom]
CROSSREFS
Sequence in context: A150331 A150332 A150333 * A217138 A004300 A049369
KEYWORD
nonn,nice,more
AUTHOR
N. J. A. Sloane, Nov 04 2000
EXTENSIONS
a(10)-a(14) from Aaron N. Siegel, May 12 2022
STATUS
approved