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

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A083043 Integers y such that 11x^2-9y^2=2 for some integer x. 5
1, 21, 419, 8359, 166761, 3326861, 66370459, 1324082319, 26415275921, 526981436101, 10513213446099, 209737287485879, 4184232536271481, 83474913437943741, 1665314036222603339, 33222805811014123039 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..15.

Tanya Khovanova, Recursive Sequences

Index entries for two-way infinite sequences

Index entries for linear recurrences with constant coefficients, signature (20,-1)

FORMULA

G.f.: (1+x)/(1-20*x+x^2). a(n)=20*a(n-1)-a(n-2). a(-1-n)=-a(n).

11*A075839(n)^2-9*a(n)^2=2.

a(n+1)=10*a(n)+sqrt(99*a(n)^2+22). - Richard Choulet, Sep 27 2007

MATHEMATICA

LinearRecurrence[{20, -1}, {1, 21}, 30] (* Harvey P. Dale, Jun 02 2014 *)

PROG

(PARI) a(n)=subst(poltchebi(n+1)-poltchebi(n), x, 10)/9

CROSSREFS

Sequence in context: A219308 A020534 A106656 * A162807 A097833 A163145

Adjacent sequences:  A083040 A083041 A083042 * A083044 A083045 A083046

KEYWORD

easy,nonn

AUTHOR

Michael Somos, Apr 17 2003

EXTENSIONS

Corrected by T. D. Noe, Nov 07 2006

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy .

Last modified November 18 12:21 EST 2017. Contains 294891 sequences.