A337391 a(n) is the smallest n-digit number divisible by n^3.

1, 16, 108, 1024, 10000, 100008, 1000188, 10000384, 100000575, 1000000000, 10000001319, 100000001088, 1000000000792, 10000000000536, 100000000001250, 1000000000000000, 10000000000001886, 100000000000001952, 1000000000000003324, 10000000000000000000, 100000000000000008972, 1000000000000000009208

Offset: 1

Author

Lukas R. Mansour, Aug 25 2020

Keywords

• nonn
• easy
• base

Examples

			a(2) = 16, as 16 is the first 2-digit number divisible by 2^3 = 8.
a(3) = 108, as 108 is the first 3-digit number divisible by 3^3 = 27.
a(4) = 1024, as 1024 is the first 4-digit number divisible by 4^3 = 64.
a(5) = 10000, as 10000 is the first 5-digit number divisible by 5^3 = 125.
		

Crossrefs

Cf. A000578, A011557, A053041 (divisible by n), A140317 (divisible by n^2).

Programs

Mathematica

Table[n^3 * Ceiling[10^(n - 1)/n^3], {n, 1, 22}] (* Amiram Eldar, Aug 25 2020 *)

PARI

a(n) = n^3 * ceil(10^(n-1) / n^3) \\ David A. Corneth, Aug 25 2020

Formula

a(n) = n^3 * ceiling(10^(n-1) / n^3). - David A. Corneth, Aug 26 2020