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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 (list; graph; refs; listen; history; text; internal format)
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.

LINKS

Table of n, a(n) for n=2..6.

Hiroaki Yamanouchi, Examples

Giovanni Resta, Illustration of a(7)>=23 and a(8)>=29

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

Adjacent sequences:  A255978 A255979 A255980 * A255982 A255983 A255984

KEYWORD

nonn,more

AUTHOR

Gordon Hamilton, Mar 13 2015

EXTENSIONS

a(5)-a(6) corrected by Hiroaki Yamanouchi, Mar 14 2015

STATUS

approved

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Last modified October 16 21:10 EDT 2019. Contains 328103 sequences. (Running on oeis4.)