A225205 Denominators of convergents to the square root of the golden ratio.

1, 3, 4, 11, 125, 386, 2055, 2441, 26465, 28906, 84277, 450291, 1435150, 7626041, 9061191, 25748423, 112054883, 137803306, 249858189, 637519684, 2799936925, 143434302859, 146234239784, 728371261995, 1602976763774, 3934324789543, 123567045239607

Offset: 0

Author

Eric W. Weisstein, May 01 2013

Keywords

• nonn
• frac

Examples

			1, 4/3, 5/4, 14/11, 159/125, 491/386, 2614/2055, 3105/2441, 33664/26465, ... = A225204/A225205
		

Links

• I. J. Good, Complex Fibonacci and Lucas Numbers, Continued Fractions, and the Square Root of the Golden Ratio (Condensed Version), Journal of the Operational Research Society, 43 (1992), 837-842.
• I. J. Good, Complex Fibonacci and Lucas Numbers, Continued Fractions, and the Square Root of the Golden Ratio, The Fibonacci Quarterly 31.1 (1993):7-20.

Crossrefs

Cf. A001622, A139339, A331692, A225204 (numerators).

Programs

Mathematica

Denominator[Convergents[Sqrt[GoldenRatio], 20]]

Formula

a(n) = A331692(n)*a(n-1) + a(n-2) for n >= 2. - Jianing Song, Aug 18 2022