A192535 Monotonic ordering of set S generated by these rules: if x and y are in S then x^2+y^2+xy is in S, and 1 is in S.

1, 3, 13, 27, 183, 217, 507, 757, 819, 1249, 2187, 33673, 34047, 36037, 39159, 47307, 47749, 50079, 53677, 100467, 120289, 141267, 257557, 258579, 263809, 271467, 383319, 414157, 573807, 575329, 583059, 594217, 671581, 673227, 681577

Offset

1,2

Comments

See A192476.

Links

Table of n, a(n) for n=1..35.

Mathematica

start = {1}; f[x_, y_] := x^2 + y^2 + 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}]]]], # <
      2000000 &]];
t = FixedPoint[b, start] (* A192535 *)

Crossrefs

Cf. A192476.

Sequence in context: A318368 A196014 A266215 * A002304 A117516 A075726

Adjacent sequences: A192532 A192533 A192534 * A192536 A192537 A192538

Keyword

nonn

Author

Clark Kimberling, Jul 04 2011

Status

approved