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A024842 a(n) = least m such that if r and s in {1/2, 1/4, 1/6, ..., 1/2n} satisfy r < s, then r < k/m < (k+2)/m < s for some integer k. 3

%I #12 Jun 27 2022 21:18:02

%S 11,29,55,89,131,181,253,323,417,505,621,727,865,989,1149,1291,1473,

%T 1633,1837,2053,2243,2481,2731,2949,3221,3505,3751,4057,4375,4649,

%U 4989,5341,5643,6017,6403,6733,7141,7561,7993,8363,8817,9283,9761,10169,10669,11181,11705

%N a(n) = least m such that if r and s in {1/2, 1/4, 1/6, ..., 1/2n} satisfy r < s, then r < k/m < (k+2)/m < s for some integer k.

%C For a guide to related sequences, see A001000. - _Clark Kimberling_, Aug 12 2012

%H Clark Kimberling, <a href="/A024842/b024842.txt">Table of n, a(n) for n = 2..100</a>

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

%t Table[While[Or @@ (Ceiling[n #1[[1]]] <

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

%t Partition[Take[seq, k], 2, 1], n++]; n, {k, 2, Length[seq]}]];

%t t = Map[leastSeparatorS[1/(2*Range[50]), #] &, Range[5]];

%t t[[3]] (* A024842 *)

%t (* _Peter J. C. Moses_, Aug 06 2012 *)

%Y Cf. A001000, A024841.

%K nonn

%O 2,1

%A _Clark Kimberling_

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Last modified May 3 19:22 EDT 2024. Contains 372222 sequences. (Running on oeis4.)