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A055850 a(n) = 3a(n-1) - a(n-2); a(0)=1, a(1)=10. 2
1, 10, 29, 77, 202, 529, 1385, 3626, 9493, 24853, 65066, 170345, 445969, 1167562, 3056717, 8002589, 20951050, 54850561, 143600633, 375951338, 984253381, 2576808805, 6746173034, 17661710297, 46238957857, 121055163274 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.

LINKS

Table of n, a(n) for n=0..25.

Index entries for linear recurrences with constant coefficients, signature (3,-1).

Tanya Khovanova, Recursive Sequences

FORMULA

a(n) = (10*(((3+sqrt(5))/2)^n - ((3-sqrt(5))/2)^n) - (((3+sqrt(5))/2)^(n-1) - ((3-sqrt(5))/2)^(n-1)))/sqrt(5).

G.f.: (1+7*x)/(1-3*x+x^2).

a(n) = Lucas(2n+1) + 6*Fibonacci(2n).

PROG

(MAGMA) [Lucas(2*n+1) + 6*Fibonacci(2*n): n in [0..30]]; // Vincenzo Librandi, Apr 18 2011

CROSSREFS

Sequence in context: A048469 A031129 A048772 * A200185 A027979 A181102

Adjacent sequences:  A055847 A055848 A055849 * A055851 A055852 A055853

KEYWORD

easy,nonn

AUTHOR

Barry E. Williams, Jun 03 2000

STATUS

approved

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Last modified November 24 00:27 EST 2017. Contains 295164 sequences.