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A162815
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a(n) = 8*a(n-1)-13*a(n-2) for n > 1; a(0) = 5, a(1) = 23.
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1
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5, 23, 119, 653, 3677, 20927, 119615, 684869, 3923957, 22488359, 128895431, 738814781, 4234877645, 24274429007, 139142022671, 797568604277, 4571702539493, 26205228460343, 150209694669335, 861009587370221
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OFFSET
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0,1
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COMMENTS
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LINKS
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FORMULA
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a(n) = ((5+sqrt(3))*(4+sqrt(3))^n+(5-sqrt(3))*(4-sqrt(3))^n)/2.
G.f.: (5-17*x)/(1-8*x+13*x^2).
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MATHEMATICA
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LinearRecurrence[{8, -13}, {5, 23}, 20] (* Harvey P. Dale, Aug 25 2017 *)
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PROG
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(Magma) [ n le 2 select 18*n-13 else 8*Self(n-1)-13*Self(n-2): n in [1..20] ];
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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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STATUS
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approved
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