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Smaller of two consecutive prime numbers such that p1*p2*d - d = average of twin prime pairs, d (delta) = p2 - p1.
13

%I #8 Dec 22 2019 08:05:01

%S 1187,8893,13967,31817,33107,56009,57587,66587,85837,87797,90547,

%T 91199,93497,101293,103177,111667,113117,127447,141397,142873,150343,

%U 150407,151667,152617,156817,157127,161977,176819,179737,186007,205957,209401

%N Smaller of two consecutive prime numbers such that p1*p2*d - d = average of twin prime pairs, d (delta) = p2 - p1.

%C See A153379 for the corresponding larger prime.

%H Amiram Eldar, <a href="/A153378/b153378.txt">Table of n, a(n) for n = 1..10000</a>

%e 1187*1193*6 - 6 = 8496540 and 8496540 +- 1 are primes, so 1187 is a term.

%t lst={};Do[p1=Prime[n];p2=Prime[n+1];d=p2-p1;a=p1*p2*d-d;If[PrimeQ[a-1]&&PrimeQ[a+1],AppendTo[lst,p1]],{n,8!}];lst

%Y Cf. A099349, A153374, A153375, A153376, A153377, A153379.

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Dec 24 2008