Solving Secret Swapping Sequences This is a cops-and-robbers challenge, the cops thread can be found here.


This is the robbers thread, your job here is to take submissions on the cops thread and try to find the hidden sequences.  If you find any sequence that can be substituted into the original code to compute that sequence that is a valid crack.  Please notify the cops of your cracks as they happen so they can update their answers.

Scoring

Your score will be the number of successful cracks you have made, with more cracks being better.
Japt, Shaggy, A000290

p#A000290uCnG


Try it online!