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A164546
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a(n) = 8*a(n-1) - 8*a(n-2) for n > 1; a(0) = 1, a(1) = 10.
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4
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1, 10, 72, 496, 3392, 23168, 158208, 1080320, 7376896, 50372608, 343965696, 2348744704, 16038232064, 109515898880, 747821334528, 5106443485184, 34868977205248, 238100269760512, 1625850340442112, 11102000565452800
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OFFSET
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0,2
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COMMENTS
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Binomial transform of A038761. Fourth binomial transform of A164640. Inverse binomial transform of A164547.
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LINKS
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FORMULA
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a(n) = 8*a(n-1) - 8*a(n-2) for n > 1; a(0) = 1, a(1) = 10.
a(n) = ((2+3*sqrt(2))*(4+2*sqrt(2))^n + (2-3*sqrt(2))*(4-2*sqrt(2))^n)/4.
G.f.: (1 + 2*x)/(1 - 8*x + 8*x^2).
a(n) = 2*(2*sqrt(2))^(n-1)*(sqrt(2)*chebyshev_U(n, sqrt(2)) + chebyshev_U(n-1, sqrt(2))). - G. C. Greubel, Jul 17 2021
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MATHEMATICA
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LinearRecurrence[{8, -8}, {1, 10}, 30] (* G. C. Greubel, Jul 17 2021 *)
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PROG
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(Magma) Z<x>:=PolynomialRing(Integers()); N<r>:=NumberField(x^2-2); S:=[ ((2+3*r)*(4+2*r)^n+(2-3*r)*(4-2*r)^n)/4: n in [0..19] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Aug 19 2009
(Sage) [2*(2*sqrt(2))^(n-1)*(sqrt(2)*chebyshev_U(n, sqrt(2)) + chebyshev_U(n-1, sqrt(2))) for n in (0..30)] # G. C. Greubel, Jul 17 2021
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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Al Hakanson (hawkuu(AT)gmail.com), Aug 15 2009
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EXTENSIONS
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STATUS
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approved
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