id:A146213 - OEIS Search Results

Search: id:A146213

Displaying 1-1 of 1 results found.

page 1

Draw lines through the vertices of a regular n-gon. a(n) is the number of intersection points outside of the n-gon.

+0
2

0, 0, 5, 18, 49, 88, 198, 300, 550, 588, 1235, 1414, 2415, 2576, 4284, 3708, 7068, 7280, 11025, 11330, 16445, 14592, 23650, 23972, 32994, 33208, 44863, 34830, 59675, 59808, 77880, 78064, 99960, 92844, 126429, 126426, 157833, 157560, 194750 (list; graph; listen)

	OFFSET	`3,3`
	COMMENT	`Note that n divides a(n). For odd n, it appears that a(n)=n(2n^3-15^2+34n-21)/24.`
	LINKS	`Jon Schoenfield, Table of n, a(n) for n = 3..100`
	FORMULA	`a(n) = A146212(n) - A007569(n).`
	CROSSREFS	`Sequence in context: A000339 A081435 A109363 this_sequence A036893 A125641 A006479` `Adjacent sequences: A146210 A146211 A146212 this_sequence A146214 A146215 A146216`
	KEYWORD	`nonn`
	AUTHOR	`T. D. Noe (noe(AT)sspectra.com), Oct 28 2008`
	EXTENSIONS	`More terms from Jon E. Schoenfield (jonscho(AT)hiwaay.net), Nov 11 2008`

page 1

Search completed in 0.002 seconds

Last modified December 15 00:47 EST 2009. Contains 170825 sequences.

AT&T Labs Research