

A061433


Largest ndigit square.


9



9, 81, 961, 9801, 99856, 998001, 9998244, 99980001, 999950884, 9999800001, 99999515529, 999998000001, 9999995824729, 99999980000001, 999999961946176, 9999999800000001, 99999999989350756, 999999998000000001
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OFFSET

1,1


COMMENTS

When (if ever) does this differ from A069659?
Trivially, 81 is both a square and a fourth power. Assuming my program works, there are no differences in the first 1500 terms.  Hans Havermann, Aug 06 2006


LINKS

Table of n, a(n) for n=1..18.


FORMULA

a(n) = (ceiling(10^(n/2))  1)^2.  Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 30 2003


EXAMPLE

a(4) = 9801 = 99^2 has 4 digits while 100^2 = 10000 has 5 digits.


MAPLE

A061433 := n>(ceil(10^(n/2))1)^2;


MATHEMATICA

Table[Floor[Sqrt[10^n1]]^2, {n, 20}] (* Harvey P. Dale, Aug 21 2014 *)


CROSSREFS

Cf. A061432.
Sequence in context: A180737 A068881 A104266 * A069659 A271556 A110853
Adjacent sequences: A061430 A061431 A061432 * A061434 A061435 A061436


KEYWORD

nonn,base,easy


AUTHOR

Amarnath Murthy, May 03 2001


EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), May 16 2001


STATUS

approved



