login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A041015 Denominators of continued fraction convergents to sqrt(11). 2
1, 3, 19, 60, 379, 1197, 7561, 23880, 150841, 476403, 3009259, 9504180, 60034339, 189607197, 1197677521, 3782639760, 23893516081, 75463188003, 476672644099, 1505481120300, 9509559365899, 30034159217997 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Sqrt(11) = 3 + continued fraction [3, 6, 3, 6, 3, 6,...] = 6/2 + 6/19 + 6/(19*379) + 6/(379*7561)... - Gary W. Adamson (qntmpkt(AT)yahoo.com), Dec 21 2007

Let X = the 2 X 2 matrix [1, 6; 3, 19], then X^n * [1, 0] = [a(n+1), a(n+2)]; e.g. X^3 * [1, 0] = [379, 1197] = [a(4), a(5)]. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Dec 21 2007

FORMULA

Empirical G.f.: (1+3*x-x^2)/(1-20*x^2+x^4). [Colin Barker, Dec 31 2011]

MATHEMATICA

Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[11], n]]], {n, 1, 50}] (*From Vladimir Joseph Stephan Orlovsky, Mar 16 2011*)

CROSSREFS

Cf. A041014.

Sequence in context: A164132 A106875 A012863 * A185448 A114250 A178747

Adjacent sequences:  A041012 A041013 A041014 * A041016 A041017 A041018

KEYWORD

nonn,cofr,easy

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 14 18:47 EST 2012. Contains 205663 sequences.