A192588 Monotonic ordering of set S generated by these rules: if x and y are in S and xy-1 is a prime, then xy-1 is in S, and 2, 4, 6, and 8 are in S.

2, 3, 4, 5, 6, 7, 8, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 61, 67, 73, 101, 103, 113, 137, 151, 163, 173, 257, 281, 401, 487, 547, 617, 677, 691, 821, 823, 977, 1093, 1123, 1303, 1381, 2467, 2707, 3701, 3907, 4933, 4937, 5413, 5527, 5861, 6737, 7817

Offset

1,1

Comments

See the discussions at A192476 and A192580.

Last term is a(61) = 62533. - Giovanni Resta, Mar 21 2013

Links

Giovanni Resta, Table of n, a(n) for n = 1..61 (full sequence)

Mathematica

start = {2, 4, 6, 8}; seq = {}; new = start; While[new != {}, seq = Union[seq, new]; fresh = new; new = {}; Do[If[PrimeQ[u = x*y - 1], If[! MemberQ[seq, u], AppendTo[new, u]]], {x, seq}, {y, fresh}]]; seq (* Giovanni Resta, Mar 21 2013 *)

Crossrefs

Cf. A192476, A192580, A192586, A192587.

Sequence in context: A167211 A362095 A067133 * A351914 A258946 A008815

Adjacent sequences: A192585 A192586 A192587 * A192589 A192590 A192591

Keyword

nonn,fini,full

Author

Clark Kimberling, Jul 05 2011

Status

approved