A192587 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.

2, 3, 4, 5, 6, 7, 11, 13, 17, 19, 23, 29, 37, 41, 43, 67, 73, 101, 113, 137, 163, 173, 257, 401, 547, 677, 691, 821, 977, 1093, 1381, 2707, 3907, 5413, 5861

Offset

1,1

Comments

See the discussions at A192476 and A192580.

Links

Table of n, a(n) for n=1..35.

Mathematica

start = {2, 4, 6}; primes = Table[Prime[n], {n, 1, 10000}];
f[x_, y_] := If[MemberQ[primes, x*y - 1], x*y - 1]
b[x_] :=
  Block[{w = x},
   Select[Union[
     Flatten[AppendTo[w,
       Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # <
      50000 &]];
t = FixedPoint[b, start]   (* A192587 *)

Crossrefs

Cf. A192476, A192580, A192586, A192588.

Sequence in context: A054010 A051948 A193461 * A174323 A103539 A174821

Adjacent sequences: A192584 A192585 A192586 * A192588 A192589 A192590

Keyword

nonn,fini,full

Author

Clark Kimberling, Jul 05 2011

Status

approved