OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
Taking the first generation of edges to be G(1) = {(1,2)}, the edge (1,2) grows G(2) = {(2,3), (2,5)}, which grows G(3) = {(3,5), (3,14), (5,21), (5,29)}, ... Expelling duplicate nodes and sorting leave (1, 2, 3, 5, 13, 16, 21, 29, 34, 160,...).
MATHEMATICA
f[x_, y_] := {{y, y^2-x^2}, {y, y^2 + x^2}}; x = 1; y = 2; t = {{x, y}};
u = Table[t = Flatten[Map[Apply[f, #] &, t], 1], {15}]; v = Flatten[u];
w = Flatten[Prepend[Table[v[[2 k]], {k, 1, Length[v]/2}], {x, y}]];
Sort[Union[w]]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Sep 08 2013
STATUS
approved