A054902 Composite numbers n such that sigma(n)+12 = sigma(n+12).

65, 170, 209, 1394, 3393, 4407, 4556, 11009, 13736, 27674, 38009, 38845, 47402, 76994, 157994, 162393, 184740, 186686, 209294, 680609, 825359, 954521, 1243574, 2205209, 3515609, 4347209, 5968502, 6539102, 6916241, 8165294, 10352294, 10595009, 10786814

Offset: 1

Author

Labos Elemer, May 23 2000

Keywords

• nonn

Examples

			n = 65, sigma(65)+12 = 84+12 = 96 = sigma(65+12) = sigma(77).
n = 11009, sigma(11009)+12 = 11220+12 = 11232 = sigma(11009+12) = sigma(11021).
		

Links

• Donovan Johnson, Table of n, a(n) for n = 1..500

Crossrefs

Complement of A046133 with respect to A015917.

Cf. A015913-A015917, A023200, A023203, A046133, A001359, A054799.

Programs

PARI

isok(n) = !isprime(n) && ((sigma(n)+12) == sigma(n+12)); \\ Michel Marcus, Dec 18 2013

Extensions

More terms from Jud McCranie, May 24 2000

Three more terms from Michel Marcus, Dec 18 2013