A349978 Lengths of optimal sparse rulers that are not Wichmann rulers.

1, 13, 17, 23, 58

Offset

1,2

Comments

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

Links

Table of n, a(n) for n=1..5.

Peter Luschny, Optimal ruler conjecture.

Eric Weisstein's World of Mathematics, Sparse Ruler.

Wikipedia, Sparse ruler.

Example

The sparse rulers of length 23 and 58 are as follows:
III........I...I..I..I.I
II..I.....I.....I.I..I.I
IIII.......................I....I...I...I...I...I...I..I..I
III...I.I........I........I........I........I..I......I..II
III.....I......II.........I.........I.........I..I...I.I..I
II.I..I..........I..I......I.......I.........I...I...I...II
II.I..I..........I......I..I..........I......I...I...I...II
II...I..I...I........I........I........I........I....II.I.I

Crossrefs

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

Sequence in context: A244078 A126143 A145483 * A125262 A163754 A104278

Adjacent sequences: A349975 A349976 A349977 * A349979 A349980 A349981

Keyword

nonn,hard,more,changed

Author

Ed Pegg Jr, Dec 07 2021

Status

approved