login
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.
3
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.
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
KEYWORD
nonn,fini,full
AUTHOR
Clark Kimberling, Jul 05 2011
STATUS
approved