id:A137720 - OEIS Search Results

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Expansion of sqrt(1-4x)/(1-3x).

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1, 1, 1, -1, -13, -67, -285, -1119, -4215, -15505, -56239, -202309, -724499, -2589521, -9254363, -33111969, -118725597, -426892131, -1539965973, -5575175319, -20260052337, -73908397851, -270657727593, -994938310059 (list; graph; listen)

	OFFSET	`0,5`
	COMMENT	`Hankel transform is A120617. In general, sqrt(1-4x)/(1-k*x) has Hankel transform with g.f. of (1-2x)/(1+2(k+2)x+4x^2).`
	FORMULA	`a(n)=sum{k=0..n, 3^k*C(2n-2k,n-k)/(1-(2n-2k))};`
	CROSSREFS	`Cf. A126966, A106191.` `Adjacent sequences: A137717 A137718 A137719 this_sequence A137721 A137722 A137723` `Sequence in context: A106975 A086689 A141956 this_sequence A093119 A137188 A055338`
	KEYWORD	`easy,sign`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Feb 08 2008`

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Last modified October 11 09:12 EDT 2008. Contains 144832 sequences.

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