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 A102807 a(n) is the square of one plus the number consisting of n 3's. 10
 1, 16, 1156, 111556, 11115556, 1111155556, 111111555556, 11111115555556, 1111111155555556, 111111111555555556, 11111111115555555556, 1111111111155555555556, 111111111111555555555556, 11111111111115555555555556, 1111111111111155555555555556, 111111111111111555555555555556 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS 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 REFERENCES Italo Ghersi, Matematica dilettevole e curiosa, pp. 111-112, Hoepli, Milano, 1967. [Vincenzo Librandi, Dec 31 2008] LINKS Seiichi Manyama, Table of n, a(n) for n = 0..500 Emile Fourrey, Récréations arithmétiques, Vuibert, 1899 and after, Paris, pages 72-73. FORMULA 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) MAPLE a:= n-> (1+parse(cat(0, 3\$n)))^2: seq(a(n), n=0..20);  # Alois P. Heinz, Sep 03 2018 CROSSREFS Cf. A052041, A093137, A075415, A109344, A104265. Sequence in context: A279295 A053903 A254333 * A160131 A206691 A064346 Adjacent sequences:  A102804 A102805 A102806 * A102808 A102809 A102810 KEYWORD nonn,base AUTHOR Ron Knott, Feb 27 2005 EXTENSIONS New name from Alois P. Heinz, Sep 03 2018 STATUS approved

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Last modified January 18 15:49 EST 2021. Contains 340254 sequences. (Running on oeis4.)