A355851 The difference between the indices of the two most recent instances of a(n-1), not including a(n-1) itself, or 0 if not enough such instances exist.

0, 0, 0, 1, 0, 1, 0, 2, 0, 2, 0, 2, 2, 2, 1, 2, 1, 9, 0, 2, 2, 4, 0, 8, 0, 4, 0, 2, 1, 2, 7, 0, 2, 2, 3, 0, 5, 0, 4, 4, 13, 0, 2, 1, 12, 0, 4, 1, 15, 0, 4, 7, 0, 4, 4, 3, 0, 3, 21, 0, 4, 1, 4, 6, 0, 3, 2, 9, 0, 5, 0, 4, 2, 24, 0, 2, 6, 0, 4, 9, 50, 0, 3, 8, 0, 4, 7, 21, 0, 3, 17

Offset

1,8

Comments

This is similar to Van Eck's sequence: A181391.

Links

Table of n, a(n) for n=1..91.

Example

Say you have 0, 0, 0, 1, 0, 1, 0, 2, 0, 2, 0, 2, 2, ?
The previous term is a 2, and the distance between the pair of most recent 2s before that is 2, hence ? = 2.

Crossrefs

Cf. A181391.

Sequence in context: A249441 A076472 A161840 * A140302 A085341 A221474

Adjacent sequences: A355848 A355849 A355850 * A355852 A355853 A355854

Keyword

nonn

Author

Eric Fox, Jul 19 2022

Status

approved