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%I #7 Sep 29 2015 14:48:57
%S 19,73,883,2593,180001,206083,388963,2268451,2836963,3612673,6329683,
%T 6415363,10342153,18800713,28486153,32080051,40878883,89753203,
%U 97050313,127552393,154844803,183169801,230953033
%N Let (p1,p2), (p3,p4) be pairs of twin primes with p1*p2=p3+p4-1; sequence gives values of p4.
%H Charles R Greathouse IV, <a href="/A047979/b047979.txt">Table of n, a(n) for n = 1..10000</a>
%e E.g. 5*7=17+19-1,11*13=71+73-1.
%o (PARI) list(lim)=my(v=List(),p=3,r); forprime(q=5,sqrtint(lim\1*2-2)+1, if(q-p==2 && isprime(r=p*q\2) && isprime(r+2), listput(v,r+2)); p=q); Vec(v) \\ _Charles R Greathouse IV_, Sep 29 2015
%o (PARI) is(n)=my(p=sqrtint(2*n-3)); p*(p+2)==2*n-3 && isprime(n) && isprime(n-2) && isprime(p) && isprime(p+2) \\ _Charles R Greathouse IV_, Sep 29 2015
%Y Cf. A047976-A047978.
%K nonn
%O 1,1
%A _Naohiro Nomoto_
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