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A255981
a(n) = greatest number of edges in a simple polygon on an n X n grid with no two edges parallel.
2
3, 5, 8, 12, 17
OFFSET
2,1
COMMENTS
Worthy of consideration to introduce slopes in the math classroom.
a(7) >= 23 and a(8) >= 29, see illustration in Links.
EXAMPLE
a(3) = 5 because of this quadrilateral in a 3 x 3 square:
1 2 .
. 4 .
5 . 3
a(4) = 8 because of this polygon:
1 3 . 4
. . 2 6
. . 5 7
. 8 . .
CROSSREFS
Cf. A271449. Construction perhaps related to construction of Costas arrays: A008404.
Sequence in context: A094913 A265060 A320849 * A020678 A310034 A014811
KEYWORD
nonn,more
AUTHOR
Gordon Hamilton, Mar 13 2015
EXTENSIONS
a(5)-a(6) corrected by Hiroaki Yamanouchi, Mar 14 2015
STATUS
approved