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A102807
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a(n) is the square of one plus the number consisting of n 3's.
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10
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1, 16, 1156, 111556, 11115556, 1111155556, 111111555556, 11111115555556, 1111111155555556, 111111111555555556, 11111111115555555556, 1111111111155555555556, 111111111111555555555556, 11111111111115555555555556, 1111111111111155555555555556, 111111111111111555555555555556
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OFFSET
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0,2
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COMMENTS
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Old name was: The number (333...334)^2.
An infinite sequence of squares with no zeros in base 10.
a(n) = A104265(2n) for n > 0. - Chai Wah Wu, Mar 24 2020
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REFERENCES
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Italo Ghersi, Matematica dilettevole e curiosa, pp. 111-112, Hoepli, Milano, 1967. [Vincenzo Librandi, Dec 31 2008]
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LINKS
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Seiichi Manyama, Table of n, a(n) for n = 0..500
Emile Fourrey, Récréations arithmétiques, Vuibert, 1899 and after, Paris, pages 72-73.
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FORMULA
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From R. J. Mathar, Jan 06 2009: (Start)
a(n) = (100^n + 4*10^n + 4)/9.
G.f.: (1 - 95*x + 490*x^2)/((1-x)*(100*x-1)*(10*x-1)). (End)
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MAPLE
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a:= n-> (1+parse(cat(0, 3$n)))^2:
seq(a(n), n=0..20); # Alois P. Heinz, Sep 03 2018
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CROSSREFS
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Cf. A052041, A093137, A075415, A109344, A104265.
Sequence in context: A279295 A053903 A254333 * A160131 A206691 A064346
Adjacent sequences: A102804 A102805 A102806 * A102808 A102809 A102810
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KEYWORD
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nonn,base
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AUTHOR
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Ron Knott, Feb 27 2005
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EXTENSIONS
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New name from Alois P. Heinz, Sep 03 2018
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STATUS
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approved
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