OFFSET
0,5
LINKS
Alois P. Heinz, Rows n = 0..150, flattened
D. Merlini, D. G. Rogers, R. Sprugnoli and M. C. Verri, On some alternative characterizations of Riordan arrays, Canad J. Math., 49 (1997), 301-320.
EXAMPLE
Triangle T(n,k) begins:
1;
1, 1;
1, 2, 2;
1, 4, 6, 6;
1, 6, 13, 19, 19;
...
MAPLE
T:= proc(n, k) option remember; `if`(n=0 and k=0, 1,
`if`(k<0 or n<k, 0, T(n-1, k)+T(n, k-1)+T(n-3, k-1)))
end:
seq(seq(T(n, k), k=0..n), n=0..12); # Alois P. Heinz, May 05 2023
CROSSREFS
KEYWORD
AUTHOR
N. J. A. Sloane, Jun 15 2002
EXTENSIONS
More terms from Joshua Zucker, May 10 2006
STATUS
approved