Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A075843
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A075843 99*a(n)^2 + 1 is a square. +0
6
0, 1, 20, 399, 7960, 158801, 3168060, 63202399, 1260879920, 25154396001, 501827040100, 10011386405999, 199725901079880, 3984506635191601, 79490406802752140, 1585823629419851199, 31636982181594271840 (list; graph; listen)
OFFSET

0,3

COMMENT

Lim. n-> Inf. a(n)/a(n-1) = 10 + 3*Sqrt(11).

Chebyshev's polynomials U(n,x) evaluated at x=10.

The a(n) give all (unsigned, integer) solutions of Pell equation b(n)^2 - 99*a(n)^2 = +1 with b(n)= A001085(n).

REFERENCES

A. H. Beiler, "The Pellian", ch. 22 in Recreations in the Theory of Numbers: The Queen of Mathematics Entertains. Dover, New York, New York, pp. 248-268, 1966.

L. E. Dickson, History of the Theory of Numbers, Vol. II, Diophantine Analysis. AMS Chelsea Publishing, Providence, Rhode Island, 1999, p. 341-400.

Peter G. L. Dirichlet, Lectures on Number Theory (History of Mathematics Source Series, V. 16); American Mathematical Society, Providence, Rhode Island, 1999, p. 139-147.

LINKS

Index entries for sequences related to linear recurrences with constant coefficients

Tanya Khovanova, Recursive Sequences

J. J. O'Connor and E. F. Robertson, Pell's Equation

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Index entries for sequences related to Chebyshev polynomials.

FORMULA

a(n) = [(10+3*Sqrt(11))^n - (10-3*Sqrt(11))^n] / (6*Sqrt(11))

a(n) = 20*a(n-1) - a(n-2), n>=1, a(0)=0, a(1)=1.

a(n) = S(n-1, 20), with S(n, x) := U(n, x/2), Chebyshev's polynomials of the second kind. S(-1, x) := 0. See A049310.

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

a(n) = sqrt((A001085(n)^2 - 1)/99).

MATHEMATICA

lst={}; Do[AppendTo[lst, GegenbauerC[n, 1, 10]], {n, 0, 8^2}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Sep 11 2008]

PROGRAM

sage: [lucas_number1(n, 20, 1) for n in xrange(0, 20)] - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 25 2008

CROSSREFS

Cf. A001084.

Adjacent sequences: A075840 A075841 A075842 this_sequence A075844 A075845 A075846

Sequence in context: A084329 A097832 A063815 this_sequence A090051 A089957 A019319

KEYWORD

nonn

AUTHOR

Gregory V. Richardson (omomom(AT)hotmail.com), Oct 14 2002

EXTENSIONS

Chebyshev and Pell comments from W. Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Nov 08 2002

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified November 8 20:39 EST 2009. Contains 166234 sequences.


AT&T Labs Research