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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).
5
8, 13, 14, 15, 30, 41, 71, 85, 97, 132, 231, 282, 424, 509, 1346, 1348, 3684
OFFSET
1,1
MATHEMATICA
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 *)
PROG
(PARI) P(n) = factorback(primes(n)); \\ A002110
isoko(k) = ispseudoprime(P(k+1)+P(k)-P(k-1)+1); \\ Michel Marcus, Sep 11 2022
KEYWORD
nonn,more
AUTHOR
Pierre CAMI, Mar 19 2007
EXTENSIONS
a(17) from Michael S. Branicky, Jun 23 2023
STATUS
approved