A013008 - OEIS

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A013008

sech(arctan(x)+tan(x))=1-4/2!*x^2+80/4!*x^4-4384/6!*x^6+451328/8!*x^8...

1, -4, 80, -4384, 451328, -74726784, 18162914304, -6087614197760, 2690808196562944, -1516485688823611392, 1061352718471077658624, -903110171035290053246976, 918161695966849718656434176 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	CROSSREFS	`Sequence in context: A012042 A013139 A013007 * A013180 A000316 A012106` `Adjacent sequences: A013005 A013006 A013007 * A013009 A013010 A013011`
	KEYWORD	`sign`
	AUTHOR	`Patrick Demichel (dml(AT)hpfrcu03.france.hp.com)`

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Last modified February 15 23:34 EST 2012. Contains 205860 sequences.