login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

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