A121598 - OEIS

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A121598

Decimal expansion of cosecant of 180/7 = 25.7142857+ degrees = csc(Pi/7).

2, 3, 0, 4, 7, 6, 4, 8, 7, 0, 9, 6, 2, 4, 8, 6, 5, 0, 5, 2, 4, 1, 1, 5, 0, 2, 2, 3, 5, 4, 6, 8, 5, 5, 1, 1, 3, 4, 4, 4, 5, 0, 1, 8, 8, 7, 6, 0, 6, 3, 2, 1, 1, 6, 2, 0, 6, 3, 1, 0, 6, 2, 9, 6, 4, 6, 6, 8, 5, 3, 3, 4, 2, 7, 7, 8, 4, 7, 9, 5, 9, 6, 3, 7, 9, 1, 1, 1, 4, 2, 1, 9, 7, 4, 7, 6, 1, 7, 9, 3, 6, 1, 5, 1, 5 (list; constant; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`1 + csc(Pi/7) is the radius of the smallest circle into which 8 unit circles can be packed ("r=3.304+ Proved by Braaksma in 1963.", according to the Friedman link, which has a diagram). csc(Pi/7) is the distance between the center of the larger circle and the center of each unit circle that touches the larger circle.`
	LINKS	`E. Friedman, Erich's Packing Center: "Circles in Circles"`
	EXAMPLE	`2.304764870962486505241150223546855...`
	PROG	`(PARI) 1/sin(Pi/7)`
	CROSSREFS	`Cf. A121570.` `Sequence in context: A133637 A010340 A049275 * A140326 A126436 A102394` `Adjacent sequences: A121595 A121596 A121597 * A121599 A121600 A121601`
	KEYWORD	`cons,nonn`
	AUTHOR	`Rick L. Shepherd (rshepherd2(AT)hotmail.com), Aug 09 2006`

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Last modified February 17 23:08 EST 2012. Contains 206085 sequences.