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A192594 Monotonic ordering of set S generated by these rules: if x and y are in S and 5x+2y is a prime, then 5x+2y is in S, and 1 is in S. 2
1, 7, 19, 37, 43, 73, 79, 97, 109, 151, 163, 181, 193, 199, 223, 229, 241, 271, 307, 313, 331, 337, 367, 373, 379, 397, 409, 421, 433, 439, 457, 463, 487, 499, 523, 541, 547, 571, 577, 601, 613, 619, 631, 643, 661, 673, 691, 709, 727, 739, 751, 757, 769 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See the discussions at A192476 and A192580.

LINKS

Table of n, a(n) for n=1..53.

MATHEMATICA

start = {1}; primes = Table[Prime[n], {n, 1, 1000}];

f[x_, y_] := If[MemberQ[primes, 5 x + 2 y], 5 x + 2 y]

b[x_] :=

Block[{w = x},

Select[Union[

Flatten[AppendTo[w,

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

Length[w]}]]]], # < 2000 &]];

t = FixedPoint[b, start] (* A192594 *)

PrimePi[t] (* A192595 *)

CROSSREFS

Cf. A192595, A192476, A192580.

Sequence in context: A068678 A069833 A215421 * A352243 A031337 A241984

Adjacent sequences: A192591 A192592 A192593 * A192595 A192596 A192597

KEYWORD

nonn

AUTHOR

Clark Kimberling, Jul 05 2011

STATUS

approved

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Last modified December 1 05:02 EST 2022. Contains 358454 sequences. (Running on oeis4.)