A024841 a(n) = least m such that if r and s in {1/1, 1/3, 1/5, ..., 1/(2n-1)} satisfy r < s, then r < k/m < (k+2)/m < s for some integer k.

5, 19, 41, 71, 109, 155, 222, 287, 376, 460, 571, 673, 806, 926, 1081, 1219, 1396, 1552, 1751, 1926, 2147, 2380, 2584, 2839, 3106, 3338, 3627, 3928, 4188, 4511, 4846, 5134, 5491, 5860, 6176, 6567, 6970, 7385, 7740, 8177, 8626, 9087, 9481, 9964, 10459, 10966, 11398

Offset

2,1

Comments

For a guide to related sequences, see A001000. - Clark Kimberling, Aug 12 2012

Links

Clark Kimberling, Table of n, a(n) for n = 2..100

Mathematica

leastSeparatorS[seq_, s_] := Module[{n = 1},
Table[While[Or @@ (Ceiling[n #1[[1]]] <
s + 1 + Floor[n #1[[2]]] &) /@ (Sort[#1, Greater] &) /@
Partition[Take[seq, k], 2, 1], n++]; n, {k, 2, Length[seq]}]];
t = Map[leastSeparatorS[1/(2*Range[50]-1), #] &, Range[5]];
t[[3]] (* A024841 *)
(* Peter J. C. Moses, Aug 06 2012 *)

Crossrefs

Cf. A001000, A024842.

Sequence in context: A262997 A031379 A125202 * A155737 A100572 A119534

Adjacent sequences: A024838 A024839 A024840 * A024842 A024843 A024844

Keyword

nonn

Author

Clark Kimberling

Status

approved