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A220121 Corresponding to the bases in A220120, the smallest primes such that there are two smaller that juxtaposed with it all 6 ways produces primes. 1
83, 97, 103, 137, 149, 181, 199, 277, 281, 389, 431, 541, 557, 617, 733, 967, 1049, 1061, 1619 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The (or one of the) pair(s) that are companion to the primes of this sequence are {5,37}, {11,41}, {23,37}, {23,67}, {37,79}, {41,131}, {37,101}, {107,199}, {241,277}, {151,199}, {79,109}, {311,409}, {257,283}, {241,317}, {223,443}, {29,293}, {23,569}, {53,383} and {509,1433}.

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

In binary (base 2), any triple of primes under 83 contains a composite among its 6 possible orders of juxtaposition.  Decimal {5,37,83} corresponds to binary {101, 100101, 1010011} and the 6 binary juxtapositions {1001011010011101, 1001011011010011, 1010011100101101,  1010011101100101, 1011001011010011, 1011010011100101} -- {38557, 38609, 42797, 42853, 45779, 46309} in decimal -- are all prime.  So, a(1)=83.

CROSSREFS

Cf. A220120.

Sequence in context: A284292 A045714 A090156 * A335916 A158719 A160028

Adjacent sequences:  A220118 A220119 A220120 * A220122 A220123 A220124

KEYWORD

nonn,base

AUTHOR

James G. Merickel, Dec 05 2012

STATUS

approved

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Last modified May 12 02:23 EDT 2021. Contains 343808 sequences. (Running on oeis4.)