A192529 Monotonic ordering of set S generated by these rules: if x and y are in S then 3xy-x-y is in S, and 2 is in S.

2, 8, 38, 176, 188, 866, 878, 938, 4040, 4256, 4316, 4328, 4388, 4688, 19850, 19910, 20186, 20198, 21206, 21278, 21566, 21578, 21638, 21938, 23438, 92576, 92912, 97820, 97880, 98900, 99176, 99248, 99260, 99536, 99548, 100916, 100928, 100988

Offset: 1

Author

Clark Kimberling, Jul 03 2011

Keywords

• nonn

Crossrefs

Cf. A192472.

Programs

Mathematica

start = {2}; f[x_, y_] := 3 x*y - x - y
b[x_] :=
  Block[{w = x},
   Select[Union[
     Flatten[AppendTo[w,
       Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # <
      1000000 &]];
t = NestList[b, start, 12][[-1]] (* A192529 *)
t/2 (* A192530 *)
Table[t[[i]] - t[[i - 1]], {i, 2, Length[t]}] (* differences *)