OFFSET
1,2
COMMENTS
T(n,n-1) = A005157(n-1)^2 for n >= 2. See Knuth (2019) link.
REFERENCES
D. E. Knuth, Email to N. J. A. Sloane, Feb 06 2019.
LINKS
Alois P. Heinz, Rows n = 1..14, flattened
Don Knuth, A conjecture about noncrossing paths, Feb 06 2019.
FORMULA
T(n,1) = binomial(2n,n) - 2.
EXAMPLE
Triangle begins:
n\d 1 2 3 4 5 6 7
1 0 0 0 0 0 0 0
2 4 0 0 0 0 0 0
3 18 25 0 0 0 0 0
4 68 386 256 0 0 0 0
5 250 4657 12200 4356 0 0 0
6 922 54219 432842 608993 123904 0 0
7 3430 642815 14697256 60650883 49489706 5909761 0
...
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
N. J. A. Sloane, Feb 07 2019
EXTENSIONS
More terms from Alois P. Heinz, Feb 07 2019
STATUS
approved