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 A108053 Maximum number of diagonals of a regular n-gon that meet at a non-center point. 0
 0, 2, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,2 LINKS B. Poonen and M Rubinstein, The Number of Intersection Points Made by the Diagonals of a Regular Polygon, 1995. Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1). FORMULA Starting at a(5) = 2, sequence is periodic with period 30. EXAMPLE In a 30-gon, there are non-center points where 7 diagonals meet, but no more than 7. Hence a(30) = 7. MATHEMATICA Join[{0, 2}, LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, {2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 7, 2, 3, 2, 3}, 103]] (* Ray Chandler, Aug 27 2015 *) CROSSREFS Sequence in context: A241476 A309727 A195719 * A327969 A328324 A133501 Adjacent sequences:  A108050 A108051 A108052 * A108054 A108055 A108056 KEYWORD easy,nonn AUTHOR David W. Wilson, Jun 01 2005 STATUS approved

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Last modified October 1 00:42 EDT 2020. Contains 337440 sequences. (Running on oeis4.)