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A143608 Numerators of the lower principal and intermediate convergents to 2^(1/2). 5
1, 4, 7, 24, 41, 140, 239, 816, 1393, 4756, 8119, 27720, 47321, 161564, 275807, 941664, 1607521, 5488420, 9369319, 31988856, 54608393 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

The lower principal and intermediate convergents to 2^(1/2), beginning with

1/1, 4/3, 7/5, 24/17, 41/29, form a strictly increasing sequence;

essentially, numerators=A143608 and denominators=A079496.

REFERENCES

Serge Lang, Introduction to Diophantine Approximations, Addison-Wesley, New York, 1966.

LINKS

John M. Campbell, An Integral Representation of Kekule' Numbers, and Double Integrals Related to Smarandache Sequences, Arxiv preprint arXiv:1105.3399, 2011.

Creighton Kenneth Dement, Comments on A143608 and A143609

C. Kimberling, Best lower and upper approximations to irrational numbers, Elem. Math. vol. 52 iss. 3 (1997) 122-126.

Index to sequences with linear recurrences with constant coefficients, signature (0,6,0,-1).

FORMULA

Conjectures: a(n)=6*a(n-2)-a(n-4). G.f.: x*(1+4*x+x^2)/((x^2-2*x-1)*(x^2+2*x-1)). a(2n)=A005319(n). a(2n+1)=A002314(n). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 17 2009]

CROSSREFS

Sequence in context: A101824 A027946 A203230 * A079441 A129418 A073218

Adjacent sequences:  A143605 A143606 A143607 * A143609 A143610 A143611

KEYWORD

nonn

AUTHOR

Clark Kimberling (ck6(AT)evansville.edu), Aug 27 2008

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Last modified February 17 00:09 EST 2012. Contains 205978 sequences.