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 A192583 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, 6, and 8 are in S. 4
 2, 4, 5, 6, 8, 11, 13, 17, 23, 31, 37, 41, 47, 53, 67, 79, 83, 89, 103, 107, 137, 139, 149, 167, 179, 223, 269, 283, 317, 359, 499, 557, 619, 643, 719, 823, 857, 1097, 1193, 1433, 1439, 1699, 1997, 2153, 2477, 2879, 3343, 4457, 6857, 7159, 8599, 12919, 41143 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See the discussion at A192580. LINKS MATHEMATICA start = {2, 4, 6, 8}; 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}]]]], # <       10000000 &]]; t = FixedPoint[b, start]  (* A192583 *) PrimePi[t] (* A192530 Nonprimes 4, 6, 8 are represented by "next prime down". *) CROSSREFS Cf. A192476. Sequence in context: A284525 A353187 A099247 * A240064 A007192 A081354 Adjacent sequences:  A192580 A192581 A192582 * A192584 A192585 A192586 KEYWORD nonn,fini,full AUTHOR Clark Kimberling, Jul 04 2011 STATUS approved

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Last modified July 1 03:30 EDT 2022. Contains 354947 sequences. (Running on oeis4.)