%I #12 Dec 09 2021 02:44:14

%S 1,13,17,23,58

%N Lengths of optimal sparse rulers that are not Wichmann rulers.

%C 58 is the last value in the Optimal Ruler Conjecture of Peter Luschny. The conjecture is known to be true to length 213.

%H Peter Luschny, <a href="http://oeis.org/wiki/User:Peter_Luschny/PerfectRulers#The_optimal_ruler_conjecture">Optimal ruler conjecture</a>.

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Sparse_ruler">Sparse ruler</a>.

%e The sparse rulers of length 23 and 58 are as follows:

%e III........I...I..I..I.I

%e II..I.....I.....I.I..I.I

%e IIII.......................I....I...I...I...I...I...I..I..I

%e III...I.I........I........I........I........I..I......I..II

%e III.....I......II.........I.........I.........I..I...I.I..I

%e II.I..I..........I..I......I.......I.........I...I...I...II

%e II.I..I..........I......I..I..........I......I...I...I...II

%e II...I..I...I........I........I........I........I....II.I.I

%Y Cf. A046693, A289761, A308766, A309407, A326499.

%K nonn,hard,more

%O 1,2

%A _Ed Pegg Jr_, Dec 07 2021