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Search: id:A087394
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%I A087394
%S A087394 11,31,59,179,599,1063,1153,1787,2381,4091,4273,5869,6661,9461,9859,
%T A087394 14867,15641,17987,20773,20899,27689,30557,39239,43651,43889,61979,
%U A087394 63391,66749,66851,68821,84347,96797,104471,111271,132949,146989,157771
%N A087394 Prime(prime(n)) when prime(prime(n)) and n are twin primes.
%e A087394 prime(103) = 563. prime(563) = 4091. 103 and 4091 are twin primes.
%o A087394 (PARI) twips(n) = { c1=0; c2=0; forprime(x=3,n, if(isprime(x+2),c1++); 
               x1=prime(prime(x)); if(isprime(x-2) || isprime(x+2), if(isprime(x1-2) 
               || isprime(x1+2), print1(x1","); c2++; ) ) ); print(); print(c2/c1+.0) 
               }
%Y A087394 Sequence in context: A144364 A031372 A028877 this_sequence A040162 A113747 
               A125239
%Y A087394 Adjacent sequences: A087391 A087392 A087393 this_sequence A087395 A087396 
               A087397
%K A087394 easy,nonn
%O A087394 3,1
%A A087394 Cino Hilliard (hillcino368(AT)gmail.com), Oct 21 2003

    
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Last modified December 20 00:58 EST 2009. Contains 171054 sequences.


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