A067475 -id:A067475 - cp's OEIS frontend

A067479 Smallest n-digit square starting with 9, or 0 if no such number exists.

9, 0, 900, 9025, 90000, 900601, 9000000, 90003169, 900000000, 9000127161, 90000000000, 900001331856, 9000000000000, 90000000369889, 900000000000000, 9000000036988900, 90000000000000000, 900000001801523401

Offset: 1

Amarnath Murthy, Feb 09 2002

Cf. A000290, A035076 (roots), A045792.

Cf. 2: A067472, 3: A067473, 4: A067474, 5: A067475, 6: A067476, 7: A067477, 8: A067478.

a(n) = if (n==2, 0, (sqrtint(9*10^(n-1)) + (n-1) % 2)^2); \\ Michel Marcus, Mar 23 2021

a(n+1) = (floor(sqrt(9*10^n)) + (n mod 2))^2, a(2)=0. - Sascha Kurz, Mar 18 2002

a(2k+1) = 9 * 10^(2k) for k >= 0. - Bernard Schott, Mar 23 2021

More terms from Sascha Kurz, Mar 18 2002

A035072 a(n) is root of square starting with digit 5: first term of runs.

Original entry on oeis.org

23, 71, 224, 708, 2237, 7072, 22361, 70711, 223607, 707107, 2236068, 7071068, 22360680, 70710679, 223606798, 707106782, 2236067978, 7071067812, 22360679775, 70710678119, 223606797750, 707106781187, 2236067977500

Offset: 2

Patrick De Geest, Nov 15 1998

Cf. A067475 (squares), A035076 (2..9).

Table[Ceiling @ Sqrt[5 * 10^n], {n, 2 , 24}] (* Amiram Eldar, Oct 08 2019 *)

a(n) = ceiling(sqrt(5*10^n)), n > 1.

cp's OEIS Frontend

A067479 Smallest n-digit square starting with 9, or 0 if no such number exists.

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