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A048479
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a(n) = T(7,n), array T given by A048472.
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1
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1, 9, 33, 97, 257, 641, 1537, 3585, 8193, 18433, 40961, 90113, 196609, 425985, 917505, 1966081, 4194305, 8912897, 18874369, 39845889, 83886081, 176160769, 369098753, 771751937, 1610612737, 3355443201, 6979321857, 14495514625, 30064771073, 62277025793
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OFFSET
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0,2
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COMMENTS
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n-th difference of a(n), a(n-1), ..., a(0) is (8, 16, 24, ...).
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LINKS
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FORMULA
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a(n) = 8*n * 2^(n-1) + 1.
a(n) = 5*a(n-1)-8*a(n-2)+4*a(n-3) for n>2. G.f.: (1+4*x-4*x^2) / ((1-x)*(1-2*x)^2). - Colin Barker, Feb 18 2016
a(n) = Sum_{k=0..n+2} Sum_{i=0..n+2} C(n+1,i) - C(k,i). - Wesley Ivan Hurt, Sep 21 2017
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MATHEMATICA
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Table[8 n*2^(n - 1) + 1, {n, 0, 29}] (* or *)
CoefficientList[Series[(1 + 4 x - 4 x^2)/((1 - x) (1 - 2 x)^2), {x, 0, 29}], x] (* Michael De Vlieger, Sep 22 2017 *)
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PROG
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(PARI) Vec((1+4*x-4*x^2)/((1-x)*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Feb 18 2016
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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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