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A154742 Denominators of the convergents of the continued fraction for sqrt{1 - 1/sqrt{2}}, the abscissa of the point of bisection of the arc of the unit lemniscate (x^2 + y^2)^2 = x^2 - y^2 in the first quadrant. 4
1, 0, 1, 1, 2, 11, 13, 24, 85, 534, 619, 2391, 7792, 80311, 810902, 891213, 1702115, 2593328, 14668755, 31930838, 110461269, 142392107, 252853376, 900952235, 5658566786, 6559519021, 58134718954, 4308528721617, 8675192162188 (list; graph; refs; listen; history; text; internal format)
OFFSET

-2,5

LINKS

G. C. Greubel, Table of n, a(n) for n = -2..1000

EXAMPLE

sqrt{1 - 1/sqrt{2}} = 0.541196100146196984399723205366... = [0; 1, 1, 5, 1, 1, 3, 6, 1, 3, 3, 10, 10, ...], the convergents of which are 0/1, 1/0, [0/1], 1/1, 1/2, 6/11, 7/13, 13/24, 46/85, 289/534, 335/619, 1294/2391, 4217/7792, ..., with brackets marking index 0. Those prior to index 0 are for initializing the recurrence.

MATHEMATICA

nmax = 100; cfrac = ContinuedFraction[ Sqrt[ 1 - 1/Sqrt[2] ], nmax + 1]; Join[ {1, 0}, Denominator[ Table[ FromContinuedFraction[ Take[cfrac, j] ], {j, 1, nmax + 1} ] ] ]

CROSSREFS

Cf. A154739, A154740 and A154741 for the decimal expansion, the continued fraction and the numerators of the convergents.

Sequence in context: A042453 A041885 A247338 * A257329 A063587 A038972

Adjacent sequences:  A154739 A154740 A154741 * A154743 A154744 A154745

KEYWORD

nonn,frac,easy

AUTHOR

Stuart Clary, Jan 14 2009

STATUS

approved

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Last modified June 17 19:02 EDT 2019. Contains 324198 sequences. (Running on oeis4.)