A192589 Monotonic ordering of set S generated by these rules: if x and y are in S and xy+3 is a prime, then xy+3 is in S, and 2 and 4 are in S.

2, 4, 7, 11, 17, 19, 31, 37, 41, 47, 71, 79, 97, 127, 151, 167, 191, 197, 257, 337, 397, 607, 677, 797, 1031, 1217, 1597, 2437, 2711, 3191, 4127, 4871, 4877, 10847, 43391

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}; primes = Table[Prime[n], {n, 1, 40000}];
f[x_, y_] := If[MemberQ[primes, x*y + 3], x*y + 3]
b[x_] :=
  Block[{w = x},
   Select[Union[
     Flatten[AppendTo[w,
       Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # <
      200000 &]];
t = FixedPoint[b, start]    (* A192589 *)

Crossrefs

Cf. A192476 and A192580.

Sequence in context: A153535 A116615 A053145 * A266448 A101978 A076273

Adjacent sequences: A192586 A192587 A192588 * A192590 A192591 A192592

Keyword

nonn,fini,full

Author

Clark Kimberling, Jul 05 2011

Status

approved