A192528 Monotonic ordering of set S generated by these rules: if x and y are in S then 5xy-x-y is in S, and 1 is in S.

1, 3, 11, 39, 43, 151, 155, 171, 543, 583, 599, 603, 619, 683, 2095, 2111, 2167, 2171, 2311, 2331, 2391, 2395, 2411, 2475, 2731, 7527, 7599, 8143, 8159, 8303, 8359, 8379, 8383, 8439, 8443, 8663, 8667, 8683, 9159, 9223, 9243, 9323, 9559, 9563

Offset: 1

Author

Clark Kimberling, Jul 03 2011

Keywords

• nonn

Crossrefs

Cf. A192476.

Programs

Mathematica

start = {1}; f[x_, y_] := 5 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}]]]], # <
      100000 &]];
t = NestList[b, start, 12][[-1]] (* A192528 *)
Table[t[[i]] - t[[i - 1]], {i, 2, Length[t]}] (* differences *)