A116025 sigma(n) plus n gives a semiprime (A001358).

7, 9, 14, 15, 17, 18, 19, 20, 22, 32, 39, 43, 45, 46, 47, 49, 50, 51, 59, 61, 62, 68, 70, 71, 72, 79, 81, 86, 91, 93, 95, 101, 104, 107, 109, 110, 115, 116, 117, 118, 121, 123, 129, 130, 142, 149, 151, 158, 160, 163, 164, 165, 167, 177, 185, 187, 197, 201, 207

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Example

sigma(101)+101=203=7*29.

Mathematica

Select[Range[300], PrimeOmega[DivisorSigma[1, #]+#]==2&] (* Harvey P. Dale, May 21 2014 *)

Crossrefs

Cf. A001358, A116014.

Sequence in context: A063189 A004472 A145827 * A344011 A320325 A320699

Adjacent sequences: A116022 A116023 A116024 * A116026 A116027 A116028

Keyword

nonn

Author

Giovanni Resta, Feb 13 2006

Status

approved