A061432 a(n) = smallest n-digit square.

1, 16, 100, 1024, 10000, 100489, 1000000, 10004569, 100000000, 1000014129, 10000000000, 100000147984, 1000000000000, 10000002149284, 100000000000000, 1000000025191729, 10000000000000000, 100000000621806289, 1000000000000000000, 10000000005259630921

Offset

1,2

Links

Robert Israel, Table of n, a(n) for n = 1..999

Formula

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

Example

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

Maple

A061432 := n->ceil(10^((n-1)/2))^2;

Mathematica

Table[Ceiling[Sqrt[10^n]]^2, {n, 0, 20}] (* Harvey P. Dale, Dec 29 2015 *)

Prog

(PARI) {a(n) = ceil(sqrt(10^n))^2}; \\ G. C. Greubel, Mar 08 2019
(Magma) [Ceiling(Sqrt(10^n))^2: n in [0..20]]; // G. C. Greubel, Mar 08 2019
(Sage) [ceil(sqrt(10^n))^2 for n in (0..20)] # G. C. Greubel, Mar 08 2019
(Python)
from math import isqrt
def A061432(n): return (isqrt(10**(n-1)-1)+1)**2 # Chai Wah Wu, Feb 20 2023

Crossrefs

Cf. A065736.

Sequence in context: A125326 A126484 A091100 * A376705 A115328 A223767

Adjacent sequences: A061429 A061430 A061431 * A061433 A061434 A061435

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