A192587 - OEIS

%I #4 Mar 30 2012 18:57:35

%S 2,3,4,5,6,7,11,13,17,19,23,29,37,41,43,67,73,101,113,137,163,173,257,

%T 401,547,677,691,821,977,1093,1381,2707,3907,5413,5861

%N Monotonic ordering of set S generated by these rules:  if x and y are in S and xy-1 is a prime, then xy-1 is in S, and 2, 4, and 6 are in S.

%C See the discussions at A192476 and A192580.

%t start = {2, 4, 6}; primes = Table[Prime[n], {n, 1, 10000}];

%t f[x_, y_] := If[MemberQ[primes, x*y - 1], x*y - 1]

%t b[x_] :=

%t   Block[{w = x},

%t    Select[Union[

%t      Flatten[AppendTo[w,

%t        Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # <

%t       50000 &]];

%t t = FixedPoint[b, start]   (* A192587 *)

%Y Cf. A192476, A192580, A192586, A192588.

%K nonn,fini,full

%O 1,1

%A _Clark Kimberling_, Jul 05 2011