OFFSET
1,2
COMMENTS
After the digit 0 that starts the sequence, we have the 2nd digit of the sequence that is > 0, then the 3rd digit that is < the 2nd digit, then the 4th digit that is > the 3rd digit, the 5th digit that is < the 4th digit, etc. Considering the sequence from the digit-size point of view, we could see it as a kind of roller coaster going up one step, than down one step, than up a again one step, etc.
2-step, 3-step,... 8-step, 9-step roller-coasters sequences will be added soon to the database.
This is not a derangement of the positive integers (completed with 0) as integers like 11, 100 or 123 will never appear.
LINKS
Jean-Marc Falcoz, Table of n, a(n) for n = 1..15002
EXAMPLE
The sequence starts with 0,2,1,3,12,13,14,15,4,5,16... and indeed the digits form a kind of 1-step roller-coaster 0 < 2 > 1 < 3 > 1 < 2 > 1 < 3 > 1 < 4 > 1 < 4...
CROSSREFS
KEYWORD
AUTHOR
Eric Angelini and Jean-Marc Falcoz, Jul 31 2018
STATUS
approved