A143825 This sequence displays every positive integer exactly three times; there is one number between the first and second 1's and one number between the second and third 1's; two numbers between the first and second 2's and two numbers between the second and third 2's; ... n numbers between the first and second n's and n numbers between the second and third n's.

1, 3, 1, 4, 1, 3, 5, 6, 4, 3, 8, 10, 5, 4, 6, 7, 9, 11, 5, 8, 13, 6, 10, 7, 2, 12, 9, 2, 8, 11, 2, 7, 14, 10, 13, 16, 9, 17, 12, 18, 15, 11, 20, 21, 22, 24, 19, 14, 13, 25, 23, 12, 16, 26, 27, 17, 15, 30, 18, 31, 28, 32, 14, 20, 34, 21, 19, 22, 33, 16, 24, 36, 15, 17, 23, 25, 35, 18, 37

Offset: 1

Author

Eric Angelini, Sep 02 2008

Keywords

• base
• nonn

Comments

The sequence displaying every positive integer exactly twice is A026272. Construction method: we always fill the next empty "hole" with the smallest available integer. There is no proof that this sequence could go on forever. Terms computed by Gilles Sadowski.

Links

• Eric Angelini, Kimberlike sequences
• E. Angelini, Kimberlike sequences [Cached, with permission]