A394212 Difference set of Mian-Chowla sequence in order of appearance.

1, 3, 2, 7, 6, 4, 12, 11, 9, 5, 20, 19, 17, 13, 8, 30, 29, 27, 23, 18, 10, 44, 43, 41, 37, 32, 24, 14, 65, 64, 62, 58, 53, 45, 35, 21, 80, 79, 77, 73, 68, 60, 50, 36, 15, 96, 95, 93, 89, 84, 76, 66, 52, 31, 16, 122, 121, 119, 115, 110, 102

Offset

1,2

Comments

Given by a greedy algorithm which constructs the Mian-Chowla sequence by taking an integer and checking whether its differences already occur in the difference set and then adding them to it.

It is not known whether it contains all positive integers or not. The least unknown number is 33.

The behavior of the sequence is cascade-like and is best seen by examining its difference sequence, which gives A394213.

Links

Sean A. Irvine, Table of n, a(n) for n = 1..10000

Thomas Bloom, Problem 340, Erdős Problems.

Example

1 = 2 - 1; 3 = 4 - 1; 2 = 4 - 2.

Crossrefs

Difference set of A005282. See A394213 and A394214.

Sequence in context: A072764 A364832 A349890 * A130328 A228993 A083569

Adjacent sequences: A394209 A394210 A394211 * A394213 A394214 A394215

Keyword

nonn

Author

Yaroslav Deryavko, Mar 12 2026

Status

approved