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A276922
Number T(n,k) of ordered set partitions of [n] where the maximal block size equals k; triangle T(n,k), n>=0, 0<=k<=n, read by rows.
14
1, 0, 1, 0, 2, 1, 0, 6, 6, 1, 0, 24, 42, 8, 1, 0, 120, 330, 80, 10, 1, 0, 720, 2970, 860, 120, 12, 1, 0, 5040, 30240, 10290, 1540, 168, 14, 1, 0, 40320, 345240, 136080, 21490, 2464, 224, 16, 1, 0, 362880, 4377240, 1977360, 326970, 38808, 3696, 288, 18, 1
OFFSET
0,5
LINKS
FORMULA
E.g.f. for column k>0: 1/(1-Sum_{i=1..k} x^i/i!) - 1/(1-Sum_{i=1..k-1} x^i/i!).
T(n,k) = A276921(n,k) - A276921(n,k-1) for k>0. T(n,0) = A000007(0).
EXAMPLE
Triangle T(n,k) begins:
1;
0, 1;
0, 2, 1;
0, 6, 6, 1;
0, 24, 42, 8, 1;
0, 120, 330, 80, 10, 1;
0, 720, 2970, 860, 120, 12, 1;
0, 5040, 30240, 10290, 1540, 168, 14, 1;
0, 40320, 345240, 136080, 21490, 2464, 224, 16, 1;
...
MAPLE
A:= proc(n, k) option remember; `if`(n=0, 1, add(
A(n-i, k)*binomial(n, i), i=1..min(n, k)))
end:
T:= (n, k)-> A(n, k) -`if`(k=0, 0, A(n, k-1)):
seq(seq(T(n, k), k=0..n), n=0..10);
MATHEMATICA
A[n_, k_] := A[n, k] = If[n == 0, 1, Sum[A[n - i, k]*Binomial[n, i], {i, 1, Min[n, k]}]]; T[n_, k_] := A[n, k] - If[k == 0, 0, A[n, k - 1]]; Table[T[n, k], {n, 0, 10}, { k, 0, n}] // Flatten (* Jean-François Alcover, Feb 11 2017, translated from Maple *)
CROSSREFS
Columns k=0-10 give: A000007, A000142 (for n>0), A320758, A320759, A320760, A320761, A320762, A320763, A320764, A320765, A320766.
Row sums give A000670.
T(2n,n) gives A276923.
Sequence in context: A111184 A111596 A271703 * A129062 A281662 A163936
KEYWORD
nonn,tabl
AUTHOR
Alois P. Heinz, Sep 22 2016
STATUS
approved