1,2

See the discussions at A192476 and A192580.

Table of n, a(n) for n=1..5.

start = {1}; primes = Table[Prime[n], {n, 1, 40000}];

f[x_, y_] := If[MemberQ[primes, x^2 + y^2 + 1], x^2 + y^2 + 1]

b[x_] :=

Block[{w = x},

Select[Union[

Flatten[AppendTo[w,

Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # <

200000 &]];

t = FixedPoint[b, start] (* A192591 *)

Cf. A192476, A192580.

Sequence in context: A088733 A128996 A196174 * A075226 A192598 A028978

Adjacent sequences: A192588 A192589 A192590 * A192592 A192593 A192594

nonn,fini,full

Clark Kimberling, Jul 05 2011

approved