login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Least m > 0 such that for every r and s in the set S = {{h*(1+sqrt(5))/2} : h = 1,..,n} of fractional parts, if r < s, then r < k/m < s for some integer k; m is the least separator of S as defined at A001000.
4

%I #11 Mar 01 2014 09:45:48

%S 2,3,4,5,6,8,8,10,10,13,13,13,16,16,16,21,21,21,21,21,28,30,30,30,34,

%T 34,34,34,34,34,34,34,34,43,45,50,50,50,50,55,55,55,55,55,55,55,55,55,

%U 55,55,55,55,55,55,72,73,73,73,81,81,81,81,81,81,89,89,89,89

%N Least m > 0 such that for every r and s in the set S = {{h*(1+sqrt(5))/2} : h = 1,..,n} of fractional parts, if r < s, then r < k/m < s for some integer k; m is the least separator of S as defined at A001000.

%C a(n) is the least separator of S, as defined at A001000, which includes a guide to related sequences. - _Clark Kimberling_, Aug 12 2012

%H Clark Kimberling, <a href="/A214964/b214964.txt">Table of n, a(n) for n = 2..300</a>

%t leastSeparatorShort[seq_, s_] := Module[{n = 1},

%t While[Or @@ (n #1[[1]] <= s + Floor[n #1[[2]]] &) /@ (Sort[#1, Greater] &) /@

%t Partition[seq, 2, 1], n++]; n];

%t Table[leastSeparatorShort[Sort[N[FractionalPart[GoldenRatio*Range[n]], 50]], 1], {n, 2, 100}]

%t (* _Peter J. C. Moses_, Aug 01 2012 *)

%Y Cf. A001000, A214961, A214965.

%K nonn

%O 2,1

%A _Clark Kimberling_, Aug 12 2012