%I A049097
%S A049097 2,5,13,29,37,41,61,73,101,109,113,137,157,173,181,193,229,257,277,281,
%T A049097 313,317,353,373,389,397,401,409,421,433,457,461,509,541,569,601,613,
%U A049097 617,641,653,661,673,677,709,733,757,761,769,797,821,829,853,857,877
%N A049097 Primes p such that p+1 is square-free.
%C A049097 n such that core(sigma(n))=n+1 where core(x) is the square-free part 
               of x. - Benoit Cloitre (benoit7848c(AT)orange.fr), May 01 2002
%C A049097 A160696(a(n)) = 1. [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), 
               May 24 2009]
%e A049097 29 is included since 29+1=30=2*3*5 is free of squares, 17 is not here 
               because 18 is divided by a square,9.
%t A049097 lst={};Do[p=Prime[n];If[ !SquareFreeQ[Floor[p-1]]&&SquareFreeQ[Floor[p+1]],
               AppendTo[lst,p]],{n,6!}];lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), 
               Dec 20 2008]
%Y A049097 Cf. A000040, A005117, A039787.
%Y A049097 Sequence in context: A026522 A122491 A002559 this_sequence A045366 A158708 
               A093702
%Y A049097 Adjacent sequences: A049094 A049095 A049096 this_sequence A049098 A049099 
               A049100
%K A049097 nonn
%O A049097 1,1
%A A049097 Labos E. (labos(AT)ana.sote.hu)