login
Lexicographically first sequence of different terms, starting with a(1) = 0 and showing a 3-step roller coaster of digits (see the Comments section).
2

%I #5 Aug 03 2018 08:15:30

%S 0,1,2,3,210,4,5,6,32,12,7,8,42,13,45,43,14,56,52,15,67,53,16,78,54,

%T 17,89,62,123,9,63,23,46,310,18,92,10,24,64,20,25,65,21,26,72,101,27,

%U 320,28,93,102,34,321,35,73,103,47,410,36,74,30,37,82,104,57,420,38,94,31,48,95,40,58,96,41

%N Lexicographically first sequence of different terms, starting with a(1) = 0 and showing a 3-step roller coaster of digits (see the Comments section).

%C 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, then the 5th digit that is < the 4th digit, then the 6th digit that is < the 5th digit, etc. Considering the sequence from the digit-size point of view, we could see it as a kind of roller coaster going up three steps, than down three steps, than up a again three steps, etc.

%H Jean-Marc Falcoz, <a href="/A317550/b317550.txt">Table of n, a(n) for n = 1..2005</a>

%e The sequence starts with 0,1,2,3,210,4,5,6,32,12,7,8,42,13,... and indeed the digits form a kind of 3-step roller-coaster 0 < 1 < 2 < 3 > 2 > 1 > 0 < 4 < 5 < 6 > 3 > 2 > 1 < 2 < 7 < 8 > 4 > 2 > 1...

%Y Cf. A317548 (1-step roller coaster) and A317549 (2-step roller coaster).

%K base,nonn,look

%O 1,3

%A _Eric Angelini_ and _Jean-Marc Falcoz_, Aug 03 2018