%I #12 Feb 10 2014 01:35:04
%S 12,18,24,32,42,48,54,60,72,80,84,90,98,104,108,114,128,132,140,152,
%T 168,180,182,192,224,228,234,240,252,264,270,272,294,308,312,360,384,
%U 390,420,432,434,440,444,450,468,480,492,504,522,558,570,572,588,594,600
%N Values of sigma(p) of primes p such that sigma(p) = sigma(c) has solution for some composite number c.
%C Corresponding values of sigma(p) of primes p from A158913.
%F a(n) = A158913(n) + 1.
%t Union@ Select[ DivisorSigma[1, Select[ Range@ 100, !PrimeQ@# &]], PrimeQ[# - 1] &] (* _Robert G. Wilson v_, Feb 09 2012 *)
%Y Cf. A158913 (primes p such that there is a composite c with sigma(p)=sigma(c)), A206448 (values of sigma(c) of composite numbers c such that sigma(c) = sigma(d) has solution for any other composite number d), A000203.
%K nonn
%O 1,1
%A _Jaroslav Krizek_, Feb 07 2012
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