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A192584 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, 8, and 10 are in S. 3

%I #7 Mar 21 2013 13:14:03

%S 2,4,5,6,8,10,11,13,17,23,31,37,41,47,53,61,67,79,83,89,101,103,107,

%T 131,137,139,149,167,179,223,263,269,283,311,317,359,367,499,557,607,

%U 619,643,719,787,809,823,857,1031,1049,1097,1193,1433,1439,1579,1619

%N 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, 8, and 10 are in S.

%C See the discussions at A192580 and A192584. The number of terms in this finite sequence is 104. The greatest term is 15845273.

%H Giovanni Resta, <a href="/A192584/b192584.txt">Table of n, a(n) for n = 1..104</a> (full sequence)

%t start = {2, 4, 6, 8, 10}; seq = {}; new = start; While[new != {},

%t 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 *)

%Y Cf. A192476, A192580, A192583.

%K nonn,fini,full

%O 1,1

%A _Clark Kimberling_, Jul 04 2011

%E Corrected by _Giovanni Resta_, Mar 21 2013

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Last modified April 25 07:07 EDT 2024. Contains 371964 sequences. (Running on oeis4.)