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Search: id:A018913
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| A018913 |
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a(n) = 9a(n - 1) - a(n - 2); a(0) = 0, a(1) = 1. |
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+0 13
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| 0, 1, 9, 80, 711, 6319, 56160, 499121, 4435929, 39424240, 350382231, 3114015839, 27675760320, 245967827041, 2186034683049, 19428344320400, 172669064200551, 1534593233484559, 13638670037160480, 121213437100959761
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Define the sequence L(a_0,a_1) by a_{n+2} is the greatest integer such that a_{n+2}/a_{n+1}<a_{n+1}/a_n for n >= 0. This is L(1,9).
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REFERENCES
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D. W. Boyd, Linear recurrence relations for some generalized Pisot sequences, Advances in Number Theory ( Kingston ON, 1991) 333-340, Oxford Sci. Publ., Oxford Univ. Press, New York, 1993;.
E. I. Emerson, Recurrent Sequences in the Equation DQ^2=R^2+N, Fib. Quart., 7 (1969).
A. F. Horadam, Special properties of the sequence W_n(a,b; p,q), Fib. Quart., 5.5 (1967), 424-434. Case a=0,b=1; p=9, q=-1.
W. Lang, On polynomials related to powers of the generating function of Catalan's numbers, Fib. Quart. 38,5 (2000) 408-419; Eq.(44), lhs, m=11.
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LINKS
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Index entries for sequences related to linear recurrences with constant coefficients
Tanya Khovanova, Recursive Sequences
Index entries for sequences related to Chebyshev polynomials.
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FORMULA
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G.f.: 1/(1-9*x+x^2).
a(n) = S(2*n-1, sqrt(11))/sqrt(11) = S(n-1, 9); S(n, x) := U(n, x/2), Chebyshev polynomials of 2nd kind, A049310. S(-1, x) := 0.
a(n)={[(9+sqrt(77))/2]^n - [(9-sqrt(77))/2]^n}/sqrt(77). G.f.(x)=x/(1-9*x+x^2). - Barry E. Williams, Aug 21 2000
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PROGRAM
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sage: [lucas_number1(n, 9, 1) for n in range(22)] - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 25 2008
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CROSSREFS
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Cf. A000027, A001906, A001353, A004254, A001109, A004187, A001090.
Cf. A056918(n)=sqrt{77*(a(n))^2 +4}, that is, a(n)=sqrt((A056918(n)^2 - 4)/77).
Sequence in context: A083411 A171314 A081108 this_sequence A127265 A055070 A143848
Adjacent sequences: A018910 A018911 A018912 this_sequence A018914 A018915 A018916
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KEYWORD
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easy,nonn
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AUTHOR
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R. K. Guy (rkg(AT)cpsc.ucalgary.ca)
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Sep 07 2000
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