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A131959
Numbers k such that 1 + Product_{j=1..k} prime(j)^prime(k-j+1) is prime.
1
OFFSET
1,2
COMMENTS
A131958 gives the corresponding primes.
a(5) > 200, if it exists. - Michael S. Branicky, Sep 04 2024
EXAMPLE
1 + (2^5)*(3^3)*(5^2) = 21601 is the prime for the term 3.
PROG
(PARI) isok(k) = isprime(1 + prod(j=1, k, prime(j)^prime(k-j+1))); \\ Michel Marcus, Jan 09 2021
CROSSREFS
Cf. A131958.
Sequence in context: A201363 A088332 A357064 * A202688 A021046 A138180
KEYWORD
hard,nonn,more
AUTHOR
Rick L. Shepherd, Aug 01 2007
STATUS
approved