A282665 - OEIS

%I #15 Jan 19 2019 03:53:56

%S 0,2,1,4,3,6,5,8,7,80,20,22,12,14,16,18,24,21,26,28,34,36,38,40,42,41,

%T 44,43,46,48,56,58,60,62,61,64,63,66,65,68,78,82,81,84,83,86,85,88,87,

%U 800,200,202,120,204,121,206,122,124,126,128,140,208,141,212,142,144,143,400,214,146,148,160,216,161,218,162,164,163

%N The larger term of the pair (a(n), a(n+1)) is always even and the larger digit of any pair of adjacent digits is also even.

%C The sequence is started with a(1) = 0 and always extended with the smallest integer not yet present and not leading to a contradiction. If two successive digits are equal (e.g., 2,2) we accept that there is a "larger one" (2).

%H Jean-Marc Falcoz, <a href="/A282665/b282665.txt">Table of n, a(n) for n = 1..10001</a>

%e In the 1st pair of integers (0,2) the larger term is (2), which is even;

%e in the 2nd pair of integers (2,1) the larger term is (2), which is even;

%e in the 3rd pair of integers (1,4) the larger term is (4), which is even;

%e in the 4th pair of integers (4,3) the larger term is (4), which is even;

%e ...

%e in the 9th pair of integers (7,80) the larger term is (80), which is even;

%e in the 10th pair of integers (80,20) the larger term is (80), which is even;

%e in the 11th pair of integers (20,22) the larger term is (22), which is even; etc.

%e In the 1st pair of digits (0,2) the larger digit is (2), which is even;

%e in the 2nd pair of digits (2,1) the larger digit is (2), which is even;

%e in the 3rd pair of digits (1,4) the larger digit is (4), which is even;

%e in the 4th pair of digits (4,3) the larger digit is (4), which is even;

%e ...

%e in the 9th pair of digits (7,8) the larger digit is (8), which is even;

%e in the 10th pair of digits (8,0) the larger digit is (8), which is even;

%e in the 11th pair of digits (0,2) the larger digit is (2), which is even; etc.

%Y Cf. A282664 (odd rather than even).

%K nonn,base

%O 1,2

%A _Eric Angelini_ and _Jean-Marc Falcoz_, Feb 20 2017