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A055271
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a(n)=5a(n-1)-a(n-2); a(0)=1, a(1)=7.
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2
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1, 7, 34, 163, 781, 3742, 17929, 85903, 411586, 1972027, 9448549, 45270718, 216905041, 1039254487, 4979367394, 23857582483, 114308545021, 547685142622, 2624117168089, 12572900697823, 60240386321026, 288629030907307
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| 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
| Index entries for sequences related to linear recurrences with constant coefficients
Tanya Khovanova, Recursive Sequences
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FORMULA
| a(n)={7*[((5+sqrt(21))/2)^n-((5-sqrt(21))/2)^n]-[((5+sqrt(21))/2)^(n-1)-((5-sqrt(21))/2)^(n-1)]}/sqrt(21)
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EXAMPLE
| G.f.=(1+2x)/(1-5x+x^2).
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CROSSREFS
| Cf. A030221.
Sequence in context: A099242 A032206 A124466 * A027209 A080048 A177140
Adjacent sequences: A055268 A055269 A055270 * A055272 A055273 A055274
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KEYWORD
| easy,nonn
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AUTHOR
| Barry E. Williams, May 10 2000
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), May 22 2000
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