

A110056


Least prime that ends a complete Cunningham chain (of the first kind) of length n.


4



13, 7, 167, 4079, 47, 2879, 71850239, 2444789759, 21981381119, 13357981992959, 681004115066879, 1136001594224639, 16756459239477534719, 781558105952602767359
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OFFSET

1,1


COMMENTS

"Complete" means that this chain is not part of a longer Cunningham chain of the first kind.
Next term is greater than 4*10^17.


LINKS



EXAMPLE

41>83>167 is a Cunningham chain of the first kind. It is complete because neither (411)/2 nor 2*167+1 is prime. It is the first such chain of three primes, so a(3) = 167.


CROSSREFS

Cf. A005384, A005385, A007700, A023272, A023302, A023330, A059452, A057326, A059455, A059761, A059762, A059763, A059764, A074313.
Cf. A110059 for Cunningham chains of the second kind.


KEYWORD

nonn,hard


AUTHOR



EXTENSIONS



STATUS

approved



