OFFSET
0,6
LINKS
Alois P. Heinz, Rows n = 0..21, flattened
Wikipedia, Permutation
EXAMPLE
T(3,0) = 1: (1)(2)(3).
T(3,1) = 2: (12)(3), (1)(23).
T(3,2) = 3: (123), (132), (13)(2).
Triangle T(n,k) begins:
1;
1;
1, 1;
1, 2, 3;
1, 3, 7, 11, 2;
1, 4, 12, 28, 53, 12, 10;
1, 5, 18, 52, 135, 289, 84, 72, 58, 6;
1, 6, 25, 84, 257, 734, 1825, 524, 564, 496, 422, 60, 42;
...
MAPLE
b:= proc(n, s) option remember; `if`(n=0, 1, (k-> `if`(n>k,
b(n-1, s)+add(b(n-1, subs(h=h+[0, 1], s)), h=s), 0)+
`if`(n>k+1, b(n-1, {s[], [n, 1]}), 0)+add(h[2]!*expand(
x^(h[1]-n)*b(n-1, s minus {h})), h=s))(nops(s)))
end:
T:= (n, k)-> coeff(b(n, {}), x, k):
seq(seq(T(n, k), k=0..floor(n^2/4)), n=0..10);
CROSSREFS
KEYWORD
AUTHOR
Alois P. Heinz, Dec 22 2023
STATUS
approved