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.

83, 97, 103, 137, 149, 181, 199, 277, 281, 389, 431, 541, 557, 617, 733, 967, 1049, 1061, 1619

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