A082893 a(n) is the closest number to n-th prime which is divisible by n.

2, 4, 6, 8, 10, 12, 14, 16, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 76, 80, 63, 88, 92, 96, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144, 148, 152, 156, 160, 164, 168, 172, 176, 180, 184, 188, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290

Offset: 1

Author

Labos Elemer, Apr 22 2003

Keywords

• nonn

Examples

			24th prime, 89 is between 72 and 96, closer to 96, so a(24)=96;
25th prime, 97 is between 75 and 100, closer to 100, so a(25)=100.
		

Crossrefs

Cf. A082894-A082900.

Programs

Mathematica

Table[n*Floor[(Floor[n/2]+Prime[n])/n], {n, 1, 100}]

Python

from sympy import prime
def A082893(n): return (m:=prime(n)+(n>>1))-m%n # Chai Wah Wu, Apr 23 2025

Formula

a(n)=n*floor[(floor(n/2)+p(n))/n], where p(n) is the n-th prime.