id:A013209 - OEIS Search Results

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log(sech(x)+arctanh(x))=x-2/2!*x^2+7/3!*x^3-24/4!*x^4+173/5!*x^5...

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1, -2, 7, -24, 173, -1280, 11779, -120960, 1474969, -19695232, 296068991, -4847011840, 87094091589, -1687646744576, 35308668668155, -789939274514432, 18872654969343537, -478658276989173760 (list; graph; listen)

	OFFSET	`1,2`
	FORMULA	`E.g.f.: log(sech(x)+arctanh(x)).`
	PROGRAM	`(PARI) a(n)=local(y); if(n<0, 0, y=x+xO(x^n); n!polcoeff(log(1/cosh(y)+atanh(y)), n))`
	CROSSREFS	`Sequence in context: A102286 A123764 A013204 this_sequence A048506 A030017 A131430` `Adjacent sequences: A013206 A013207 A013208 this_sequence A013210 A013211 A013212`
	KEYWORD	`sign`
	AUTHOR	`Patrick Demichel (dml(AT)hpfrcu03.france.hp.com)`

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Last modified September 6 16:04 EDT 2008. Contains 143483 sequences.

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