OFFSET
0,3
COMMENTS
Also the number of ballot sequences of length 2n where n is the position of the last occurrence of the minimal value.
LINKS
Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 0..25
Wikipedia, Young tableau
FORMULA
a(n) = A238794(2n,n).
EXAMPLE
a(2) = 2:
[1 2] [1 2]
[3] [3 4]
[4]
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt and Alois P. Heinz, Jul 09 2014
STATUS
approved