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A163662
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A020988 written in base 2.
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5
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10, 1010, 101010, 10101010, 1010101010, 101010101010, 10101010101010, 1010101010101010, 101010101010101010, 10101010101010101010, 1010101010101010101010, 101010101010101010101010, 10101010101010101010101010, 1010101010101010101010101010
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OFFSET
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1,1
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COMMENTS
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The digits are n concatenated blocks of (10).
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LINKS
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FORMULA
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a(n) = Sum_{k=1..n} 10^(2k-1).
a(n) = 100*a(n-1) + 10.
a(n) = 101*a(n-1) - 100*a(n-2).
G.f.: 10*x/((100*x-1)*(x-1)). (End)
a(n) = (10/99)*(10^(2*n) - 1).
E.g.f.: (10/99)*(exp(100*x) - exp(x)). (End)
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MAPLE
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MATHEMATICA
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Table[(10/99)*(10^(2*n) - 1), {n, 1, 50}] (* G. C. Greubel, Aug 01 2017 *)
Table[FromDigits[PadRight[{}, 2n, {1, 0}]], {n, 20}] (* or *) LinearRecurrence[ {101, -100}, {10, 1010}, 20] (* Harvey P. Dale, Jan 08 2020 *)
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PROG
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(PARI) x='x+O('x^50); Vec(10*x/((100*x-1)*(x-1))) \\ G. C. Greubel, Aug 01 2017
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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STATUS
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approved
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