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A110093 Smallest prime ending (through <*2+1>) or/and <*2-1>) a complete Cunningham chain (of the first or the second kind) of length n. 0
11, 7, 5, 4079, 47, 2879, 1065601 (list; graph; refs; listen; history; text; internal format)



The word "complete" indicates each chain is exactly n primes long for the operator in function (i.e. the chain cannot be a subchain of another one); but the first and/or last term may be involved in a chain of the other kind (i.e. the chain may be connected to another one).


Table of n, a(n) for n=1..7.

Chris Caldwell's Prime Glossary, Cunningham chains.


a(1)=11 because 2, 3, 5 and 7 are not ending chains; or are part of chains longer than one prime; 11, although is part of a five primes <2p+1> chain, is isolated through <2p-1>.

a(2)=7 because 7 ends through <2p+1> the first two primes chain: 3->7 (even if both primes are also part of <2p-1> chains).


Terms computed by Gilles Sadowski


Cf. A023272, A023302, A023330, A005384, A005385, A059452, A059455, A007700, Cf. A059759, A059760, A059761, A059762, A059763, A059764, A059765, A038397, A104349, A091314, A069362, A016093, A014937, A057326, A110059, A110056, A110038, A059766, A110027, A059764, A110025, A110024, A059763, A110022, A109998, A109946, A109927, A109835, A005603.

Sequence in context: A087896 A240598 A144262 * A282345 A265765 A187563

Adjacent sequences:  A110090 A110091 A110092 * A110094 A110095 A110096




Alexandre Wajnberg, Sep 04 2005



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Last modified June 20 10:00 EDT 2021. Contains 345162 sequences. (Running on oeis4.)