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

1,1

Links

Table of n, a(n) for n=1..58.

Formula

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

Example

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.

Mathematica

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

Crossrefs

Cf. A082894-A082900.

Sequence in context: A330688 A280743 A162764 * A024807 A187908 A187233

Adjacent sequences: A082890 A082891 A082892 * A082894 A082895 A082896

Keyword

nonn

Author

Labos Elemer, Apr 22 2003

Status

approved