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A087714
Primes p = prime(i) such that p(i)# - p(i+1) and p(i)# + p(i+1) are both primes, where p# = A002110.
6
5, 13, 19, 367
OFFSET
1,1
COMMENTS
Conjecture: there are only 4 primes in this sequence.
EXAMPLE
2*3*5-7 = 23 is prime, 2*3*5+7 = 37 is prime.
PROG
(PARI) isok(p) = {if (isprime(p), my(pp = prod(k=1, primepi(p), prime(k)), q = nextprime(p+1)); isprime(pp-q) && isprime(pp+q); ); } \\ Michel Marcus, Sep 20 2019
(PARI) my(pr=1); forprime(p=1, , pr=pr*p; if(ispseudoprime(pr-nextprime(p+1)) && ispseudoprime(pr+nextprime(p+1)), print1(p, ", "))) \\ Felix Fröhlich, Sep 20 2019
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Pierre CAMI, Sep 28 2003
STATUS
approved