id:A157327 - OEIS Search Results

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Egyptian fraction expansion for Pi/4=atan(1/2)+atan(1/3) (Hutton 1776)

+0
2

2, 3, -24, -81, 160, 1215, -896, -15309, 4608, 177147, -22528, -1948617, 106496, 20726199, -491520, -215233605, 2228224, 2195382771, -9961472, -22082967873, 44040192, 219667417263, -192937984, -2165293113021, 838860800 (list; graph; listen)

	OFFSET	`0,1`
	COMMENT	`Sum_{n>=0} 1/a(n) = Pi/4`
	LINKS	`X. Gourdon and P. Sebah, The constant Pi. The classic period`
	FORMULA	`G.f.: 2(1-4x^2)/(1+4x^2)^2+3x(1-9x^2)/(1+9*x^2)^2`
	CROSSREFS	`Cf. A157142, A155988, A058962.` `Sequence in context: A061355 A160618 A057665 this_sequence A009231 A012304 A047157` `Adjacent sequences: A157324 A157325 A157326 this_sequence A157328 A157329 A157330`
	KEYWORD	`frac,sign`
	AUTHOR	`Jaume Oliver Lafont (joliverlafont(AT)gmail.com), Feb 27 2009`

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Last modified March 20 09:10 EDT 2010. Contains 173642 sequences.

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