OFFSET
0,2
COMMENTS
EXAMPLE
Write 0..n as column indices. Under each column write a number for each word of length n+1 of nonisomorphic ballot sequences on 2..(n+1), where the number is n+the number of distinct elements of 2..(n+1). So;
0 1 2 3 4 5
1 2 3 4 5 6
... 4 5 6 7
..... 6 6 7
....... 7 8
....... 8 8
......... 9
......... 10
e.g. for n=5, consider 22222, 22223, 22233, 22234, 22334, 22345, 23456, giving 6,7,7,8,8,9,10.
The sequence reads the columns in turn.
CROSSREFS
KEYWORD
hard,nonn,tabf
AUTHOR
Jon Perry, Mar 26 2004
STATUS
approved