OFFSET
1,3
COMMENTS
As the digit 0 has no predecessor and the digit 9 has no successor here, sets of successive digits like {1,0,9} and {8,9,0} are forbidden.
LINKS
Jean-Marc Falcoz, Table of n, a(n) for n = 1..624
EXAMPLE
Terms a(1) to a(10) are obvious;
a(11) is 78 because 78 is the smallest integer not yet in the sequence such that the elements of the sets {8,9,7} and {9,7,8} are three consecutive digits;
a(12) is 67 because 67 is the smallest integer not yet in the sequence such that the elements of the sets {7,8,6} and {8,6,7} are three consecutive digits;
a(13) is 56 because 56 is the smallest integer not yet in the sequence such that the elements of the sets {6,7,5} and {7,5,6} are three consecutive digits;
etc.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Jean-Marc Falcoz, Apr 03 2018
STATUS
approved