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A221907
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a(n) = 5^n + 5*n.
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2
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1, 10, 35, 140, 645, 3150, 15655, 78160, 390665, 1953170, 9765675, 48828180, 244140685, 1220703190, 6103515695, 30517578200, 152587890705, 762939453210, 3814697265715, 19073486328220, 95367431640725, 476837158203230
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f.: (1+3*x-24*x^2)/((1-x)^2*(1-5*x)).
a(n) = 7*a(n-1) - 11*a(n-2) + 5*a(n-3).
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MATHEMATICA
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Table[(5^n + 5 n), {n, 0, 30}] (* or *) CoefficientList[Series[(1 + 3 x - 24 x^2)/((1 - x)^2 (1 - 5 x)), {x, 0, 30}], x]
LinearRecurrence[{7, -11, 5}, {1, 10, 35}, 30] (* Harvey P. Dale, Jul 23 2013 *)
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PROG
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(Magma) [5^n + 5*n: n in [0..30]]; /* or */ I:=[1, 10, 35]; [n le 3 select I[n] else 7*Self(n-1)-11*Self(n-2)+5*Self(n-3): n in [1..30]];
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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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