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A070957 Primes p such that the equation sigma(x)=p has no solution. 0

%I

%S 2,5,11,17,19,23,29,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,

%T 107,109,113,131,137,139,149,151,157,163,167,173,179,181,191,193,197,

%U 199,211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293

%N Primes p such that the equation sigma(x)=p has no solution.

%o (PARI) for(n=1,100,if(sum(j=1,n,if(sigma(j)-n,1-isprime(n),1))==0,print1(n,",")))

%Y Cf. A007369.

%K easy,nonn

%O 1,1

%A _Benoit Cloitre_, May 16 2002

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Last modified November 21 09:14 EST 2019. Contains 329362 sequences. (Running on oeis4.)