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A116025 sigma(n) plus n gives a semiprime (A001358). 1

%I

%S 7,9,14,15,17,18,19,20,22,32,39,43,45,46,47,49,50,51,59,61,62,68,70,

%T 71,72,79,81,86,91,93,95,101,104,107,109,110,115,116,117,118,121,123,

%U 129,130,142,149,151,158,160,163,164,165,167,177,185,187,197,201,207

%N sigma(n) plus n gives a semiprime (A001358).

%H Harvey P. Dale, <a href="/A116025/b116025.txt">Table of n, a(n) for n = 1..1000</a>

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

%t Select[Range[300],PrimeOmega[DivisorSigma[1,#]+#]==2&] (* _Harvey P. Dale_, May 21 2014 *)

%Y Cf. A001358, A116014.

%K nonn

%O 1,1

%A _Giovanni Resta_, Feb 13 2006

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Last modified January 27 16:33 EST 2022. Contains 350609 sequences. (Running on oeis4.)