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Search: id:A054485
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| A054485 |
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A second order recursive sequence. |
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+0
2
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| 1, 7, 27, 101, 377, 1407, 5251, 19597, 73137, 272951, 1018667, 3801717, 14188201, 52951087, 197616147, 737513501, 2752437857, 10272237927, 38336513851, 143073817477, 533958756057
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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I. Adler, Three diophantine equations - Part II, Fib. Quart., 7 (1969), pps. 181-193.
A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pps. 122-125, 194-196.
E. I. Emerson, Recurrent Sequences in the Equation DQ^2=R^2+N, Fib. Quart., 7 (1969), pps. 231-242.
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LINKS
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Index entries for sequences related to linear recurrences with constant coefficients
Tanya Khovanova, Recursive Sequences
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FORMULA
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a(n)=4a(n-1)-a(n-2), a(0)=1, a(0)=7.
G.f.: (1+3*x)/(1-4*x+x^2). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 03 2008]
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EXAMPLE
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a(n)={7*([2+sqrt(3)]^n-[2-sqrt(3)]^n)-([2+sqrt(3)]^(n-1)-[2-sqrt(3)]^(n-1))}/2*sqrt(3).
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CROSSREFS
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Cf. A054491.
Adjacent sequences: A054482 A054483 A054484 this_sequence A054486 A054487 A054488
Sequence in context: A059769 A135914 A006350 this_sequence A090856 A055917 A056120
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KEYWORD
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easy,nonn
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AUTHOR
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Barry E. Williams, May 06 2000
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