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A192586 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 and 4 are in S. 3
2, 3, 4, 5, 7, 11, 13, 19, 37, 43, 73 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See the discussions at A192476 and A192580.

LINKS

Table of n, a(n) for n=1..11.

MATHEMATICA

start = {2, 4}; 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]  (* A192586 *)

CROSSREFS

Cf. A192476, A192580, A192587, A192588.

Sequence in context: A073019 A174291 A007885 * A003037 A259466 A046420

Adjacent sequences:  A192583 A192584 A192585 * A192587 A192588 A192589

KEYWORD

nonn,fini,full

AUTHOR

Clark Kimberling, Jul 05 2011

STATUS

approved

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Last modified January 24 16:34 EST 2020. Contains 331207 sequences. (Running on oeis4.)