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A082766 Series ratios converge alternately to sqrt(2) and 1+sqrt(1/2). +0
4
1, 1, 2, 3, 4, 7, 10, 17, 24, 41, 58, 99, 140, 239, 338, 577, 816, 1393, 1970, 3363, 4756, 8119, 11482, 19601, 27720, 47321, 66922, 114243, 161564, 275807, 390050, 665857, 941664, 1607521, 2273378, 3880899, 5488420, 9369319, 13250218, 22619537 (list; graph; listen)
OFFSET

1,3

COMMENT

a(2n+2)/a(2n+1) converges to sqrt(2).

a(2n+1)/a(2n) converges to 1+sqrt(1/2).

a(n+2)/a(n) converges to 1+sqrt(2).

a(2n) is A001333, a(2n+1) is A052542.

FORMULA

a(2n) = a(2n-1) + a(2n-2); a(2n+1) = a(2n) + a(2n-2)

O.g.f.: x(1-x^2+x)(x^2+1)/(1-2x^2-x^4). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 08 2008]

CROSSREFS

Cf. A001333, A052542. See A119016 for another version.

Adjacent sequences: A082763 A082764 A082765 this_sequence A082767 A082768 A082769

Sequence in context: A018143 A136570 A119016 this_sequence A082958 A060166 A053634

KEYWORD

nonn

AUTHOR

Gary W. Adamson (qntmpkt(AT)yahoo.com), May 24 2003

EXTENSIONS

Edited by Don Reble (djr(AT)nk.ca), Nov 04 2005

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Last modified October 15 20:12 EDT 2008. Contains 145099 sequences.


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