A160469 - OEIS

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A160469

A 'look-a-like' of the numerators in Taylor series for tan(x)

1, 1, 2, 17, 62, 1382, 21844, 929569, 6404582, 443861162, 18888466084, 1936767361654, 58870668456604, 8374643517010684, 689005380505609448, 129848163681107301953, 1736640792209901647222, 418781231495293038913922 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,3`
	COMMENTS	`This sequence makes its appearance as the first left hand column of 'triangle' A160468.` `The first difference with the sequence for the numerators in the Taylor series for tan(x) A002430 occurs at a(12). Its resemblance with this sequence led to the conjecture A160469(n) = A002430(n)*A089170(n-1).`
	FORMULA	`a(n) = A002430(n)A089170(n-1) with A002430 (n) = numer((-1)^(n-1)2^(2n)(2^(2n)-1) bernoulli(2n)/(2n)!) and A089170 (n-1) = numer(2bernoulli(2n)* (4^n-1)/(2n))/ numer((4^n-1)bernoulli(2n)/(2n)!) for n = 1, 2, 3, .. .\`
	CROSSREFS	`Equals the first left hand column of A160468.` `Equals A002430(n)A089170(n-1).` `Equals (A002430(n)/A036279(n))(A117972(n)/A000265(n)).` `Equals A048896(n-1)A002425(n).` `Cf. A156769 A 'look-a-like' of the denominators in Taylor series for tan(x).` `Sequence in context: A071402 A191295 A002430 A176581 A037420 A034721` `Adjacent sequences: A160466 A160467 A160468 * A160470 A160471 A160472`
	KEYWORD	`easy,nonn`
	AUTHOR	`Johannes W. Meijer (meijgia(AT)hotmail.com), May 24 2009`

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Last modified February 16 21:47 EST 2012. Contains 205978 sequences.