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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)
OFFSET

1,1

COMMENTS

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).

LINKS

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

Chris Caldwell's Prime Glossary, Cunningham chains.

EXAMPLE

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).

MAPLE

Terms computed by Gilles Sadowski

CROSSREFS

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

KEYWORD

easy,nonn

AUTHOR

Alexandre Wajnberg, Sep 04 2005

STATUS

approved

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Last modified September 25 18:21 EDT 2020. Contains 337344 sequences. (Running on oeis4.)