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A017936 Smallest number whose square has n digits. 15
1, 4, 10, 32, 100, 317, 1000, 3163, 10000, 31623, 100000, 316228, 1000000, 3162278, 10000000, 31622777, 100000000, 316227767, 1000000000, 3162277661, 10000000000, 31622776602, 100000000000, 316227766017, 1000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = ceiling(10^((n-1)/2)).

EXAMPLE

a(4) = 32, 32^2 = 1024 has 4 digits, while 31^2 = 961 has 3 digits.

MAPLE

A061436 := n->ceil(10^((n-1)/2));

MATHEMATICA

Table[Ceiling[Sqrt[10^n]], {n, 0, 30}] (* Harvey P. Dale, Jan 19 2012 *)

PROG

(MAGMA) [Ceiling(10^((n-1)/2)): n in [1..30]]; // Vincenzo Librandi, Oct 21 2011

CROSSREFS

Cf. A061432.

Sequence in context: A034717 A295404 A001673 * A033297 A129880 A303832

Adjacent sequences:  A017933 A017934 A017935 * A017937 A017938 A017939

KEYWORD

nonn,base,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

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

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 30 2003

STATUS

approved

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Last modified April 17 11:45 EDT 2021. Contains 343064 sequences. (Running on oeis4.)