[seqfan] Re: Comma-digit swap

[Graeme McRae]

In base 2, the sequences are
P=7,29,59,79,113,131,137,149,...
S=15,27,55,95,99,135,147,171,...

In base 3,
P=2,7,13,23,17,19,29,41,67,43,...
S=8,4,14,16,25,32,34,44,40,49,...

--Graeme McRae,
Palmdale, CA

On Sep 27, 2011, at 8:28 AM, Eric Angelini <Eric.Angelini at kntv.be> wrote:

> Hello Seqfans,
> 
> S = 21,12,32,91,33,1,72,111,92,231,132,272,291,273,14,15,4,34,...
> P = 2,11,23,29,13,3,17,211,19,223,113,227,229,127,31,41,5,43,4... 
> 
> S contains only non-primes which differ one from another;
> P contains only primes which differ one from another;
> and S becomes P if you permute each comma of S with its 
> closest digit on the left.
> 
> Is the above start of S the lexicographically first such one?
> In building S we have obeyed these rules:
> 
> a) Write S and P with a(n) and a(n+1) only separated by a comma;
> b) a(n) is the smallest non-prime not yet present in S such that
>   permuting the comma which follows a(n) with the last digit
>   of a(n) will produce a prime not yet present in P.
> 
> Best,
> É.
> 
> 
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