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A102807 The number (333...334)^2. 6
1, 16, 1156, 111556, 11115556, 1111155556, 111111555556, 11111115555556, 1111111155555556, 111111111555555556, 11111111115555555556, 1111111111155555555556, 111111111111555555555556, 11111111111115555555555556, 1111111111111155555555555556, 111111111111111555555555555556 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

An infinite sequence of squares with no zeros in base 10.

REFERENCES

Italo Ghersi, Matematica dilettevole e curiosa, pag. 111-112, Hoepli, Milano, 1967 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Dec 31 2008]

FORMULA

a(n)= (100^n+4*10^n+4)/9. G.f.: (1-95x+490x^2)/((1-x)(100x-1)(10x-1)). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 06 2009]

CROSSREFS

Cf. A052041, A102794.

Sequence in context: A203096 A144915 A053903 * A160131 A206691 A064346

Adjacent sequences:  A102804 A102805 A102806 * A102808 A102809 A102810

KEYWORD

nonn

AUTHOR

Ron Knott, Feb 27 2005

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Last modified February 17 19:13 EST 2012. Contains 206085 sequences.