id:A122946 - OEIS Search Results

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a(0)=a(1)=0, a(2)=a(3)=2, for n>=3 a(n)=a(n-1)+4*a(n-3).

+0
2

0, 0, 2, 2, 2, 10, 18, 26, 66, 138, 242, 506, 1058, 2026, 4050, 8282, 16386, 32586, 65714, 131258, 261602, 524458, 1049490, 2095898, 4193730, 8391690, 16775282, 33550202, 67116962, 134218090, 268418898, 536886746, 1073759106, 2147434698 (list; graph; listen)

	OFFSET	`0,3`
	COMMENT	`See lemma 5.2 of Reznick's preprint.`
	LINKS	`Bruce Reznick, Regularity properties of the Stern enumeration of the rationals.`
	FORMULA	`a(n)=(1/7)2^(-2 + n/2) (72^(n/2) - 7Cos[n(Pi - ArcTan[Sqrt[7]])] + 5Sqrt[7]* Sin[n*(-Pi + ArcTan[Sqrt[7]])]) - Zak Seidov (zakseidov(AT)yahoo.com), Oct 26 2006`
	PROGRAM	`(PARI) a0=a1=0; a2=2; for(n=3, 50, a3=a2+4*a0; a0=a1; a1=a2; a2=a3; print1(a3, ", "))`
	CROSSREFS	`Cf. A002487.` `Adjacent sequences: A122943 A122944 A122945 this_sequence A122947 A122948 A122949` `Sequence in context: A091185 A125695 A138674 this_sequence A087628 A089871 A068971`
	KEYWORD	`nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 24 2006`
	EXTENSIONS	`Entries checked by Zak Seidov, Oct 26 2006`

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Last modified October 7 14:39 EDT 2008. Contains 144666 sequences.

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