id:A121224 - OEIS Search Results

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Decimal expansion of 1/(2 tan(1/2)).

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9, 1, 5, 2, 4, 3, 8, 6, 0, 8, 5, 6, 2, 2, 5, 9, 5, 9, 6, 3, 4, 0, 0, 9, 7, 1, 9, 4, 8, 4, 4, 0, 8, 3, 1, 1, 8, 7, 9, 0, 5, 3, 9, 7, 4, 0, 0, 8, 0, 6, 7, 0, 0, 2, 1, 8, 3, 2, 0, 7, 9, 7, 3, 3, 9, 2, 7, 3, 0, 6, 1, 2, 0, 9, 8, 1, 7, 7, 5, 8, 0, 0, 5, 6, 0, 7, 3, 2, 4, 3, 8, 9, 5, 5, 2, 4, 9, 1, 3, 9, 5 (list; cons; graph; listen)

	OFFSET	`0,1`
	COMMENT	`The divergent series sum_(n>=1) sin(n) sums to this value if interpreted as a geometric series; that is, sum_(n>=1) sin(n) = Im(sum_(n>=1) e^(ni)) = Im(-e^i/(e^i-1)) = 1/(2 tan(1/2)). If x_m = sum_(0<n<m) sin(n), then (max(x_1, x_2, ...) + min(x_1, x_2, ...))/2 tends to this number. Given by the series 1+sum_(n>=1) (-1)^n B_(2n)/(2n)!. Corresponding value for cos is -1/2.`
	EXAMPLE	`a = 0.915243860856225...`
	MATHEMATICA	`RealDigits[N[1/(2 Tan[1/2]), 101]]`
	CROSSREFS	`Sequence in context: A114893 A089101 A010168 this_sequence A100924 A143296 A021526` `Adjacent sequences: A121221 A121222 A121223 this_sequence A121225 A121226 A121227`
	KEYWORD	`cons,nonn`
	AUTHOR	`Fredrik Johansson (fredrik.johansson(AT)gmail.com), Aug 20 2006`

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Last modified March 19 01:26 EDT 2010. Contains 173632 sequences.

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