OFFSET
1,2
COMMENTS
MATHEMATICA
start = {1, 2}; primes = Table[Prime[n], {n, 1, 20000}];
f[x_, y_] := If[MemberQ[primes, x^2 + 2 y^2], x^2 + 2 y^2]
b[x_] :=
Block[{w = x},
Select[Union[
Flatten[AppendTo[w,
Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1,
Length[w]}]]]], # < 30000 &]];
t = FixedPoint[b, start] (* A192612 *)
CROSSREFS
KEYWORD
nonn,full,fini
AUTHOR
Clark Kimberling, Jul 05 2011
STATUS
approved