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A128662 Numbers k such that p(k+1)# + p(k)# - p(k-1)# + 1 is prime where p(i)# = product of first i primes = A002110(i).

%I A128662 #20 Dec 12 2024 04:45:11
%S A128662 8,13,14,15,30,41,71,85,97,132,221,282,424,509,1346,1348,3684,8224
%N A128662 Numbers k such that p(k+1)# + p(k)# - p(k-1)# + 1 is prime where p(i)# = product of first i primes = A002110(i).
%t A128662 Flatten[Position[Partition[FoldList[Times,Prime[Range[1350]]],3,1],_?(PrimeQ[ #[[2]]+#[[3]]-#[[1]]+1]&),1,Heads->False]]+1 (* _Harvey P. Dale_, May 30 2018 *)
%o A128662 (PARI) P(n) = factorback(primes(n)); \\ A002110
%o A128662 isok(k) = ispseudoprime(P(k+1)+P(k)-P(k-1)+1); \\ _Michel Marcus_, Sep 11 2022
%Y A128662 Cf. A002110, A128420, A128421, A128657, A128658, A128659, A128660, A128661.
%K A128662 nonn,more
%O A128662 1,1
%A A128662 _Pierre CAMI_, Mar 19 2007
%E A128662 a(17) from _Michael S. Branicky_, Jun 23 2023
%E A128662 a(11) corrected and a(18) from _Michael S. Branicky_, Dec 11 2024