A080575 Triangle of multinomial coefficients, read by rows (version 2).

1, 1, 1, 1, 3, 1, 1, 4, 3, 6, 1, 1, 5, 10, 10, 15, 10, 1, 1, 6, 15, 15, 10, 60, 20, 15, 45, 15, 1, 1, 7, 21, 21, 35, 105, 35, 70, 105, 210, 35, 105, 105, 21, 1, 1, 8, 28, 28, 56, 168, 56, 35, 280, 210, 420, 70, 280, 280, 840, 560, 56, 105, 420, 210, 28, 1, 1, 9, 36, 36, 84, 252, 84, 126, 504, 378, 756, 126, 315, 1260, 1260, 1890, 1260, 126, 280, 2520, 840, 1260, 3780, 1260, 84, 945, 1260, 378, 36, 1, 1, 10, 45, 45, 120, 360, 120, 210, 840, 630, 1260, 210

Offset: 1

Author

Wouter Meeussen, Mar 23 2003

Keywords

• nonn
• easy
• nice
• tabf
• look

Comments

This is different from A036040 and A178867.

T[n,m] = count of set partitions of n with block lengths given by the m-th partition of n in the canonical ordering.

From Tilman Neumann, Oct 05 2008: (Start)

These are also the coefficients occurring in complete Bell polynomials, Faa di Bruno's formula (in its simplest form) and computation of moments from cumulants.

Though the Bell polynomials seem quite unwieldy, they can be computed easily as the determinant of an n-dimensional square matrix. (see e.g. [Coffey] and program below)

The complete Bell polynomial of the first n primes gives A007446. (End)

The difference with A036040 and A178867 lies in the ordering of the monomials. This sequence uses lexicographic ordering, while in A036040 the total order (power) of the monomials prevails (Abramowitz-Stegun style): e.g., in row 6 we have ...+ 15*x[3]*x[5] + 15*x[3]*x[6]^2 + 10*x[4]^2 +...; in A036040 the coefficient of x[3]*x[6]^2 would come after that of x[4]^2 because the total order is higher, here it comes before in view of the lexicographic order. - M. F. Hasler, Jul 12 2015

Examples

			For n=4 the 5 integer partitions in canonical ordering with corresponding set partitions and counts are:
   [4]       -> #{1234} = 1
   [3,1]     -> #{123/4, 124/3, 134/2, 1/234} = 4
   [2,2]     -> #{12/34, 13/24, 14/23} = 3
   [2,1,1]   -> #{12/3/4, 13/2/4, 1/23/4, 14/2/3, 1/24/3, 1/2/34} = 6
   [1,1,1,1] -> #{1/2/3/4} = 1
Thus row 4 is [1, 4, 3, 6, 1].
Triangle begins:
1;
1, 1;
1, 3,  1;
1, 4,  3,  6,  1;
1, 5, 10, 10, 15,  10,  1;
1, 6, 15, 15, 10,  60, 20, 15,  45,  15,  1;
1, 7, 21, 21, 35, 105, 35, 70, 105, 210, 35, 105, 105, 21, 1;
...
Row 4 represents 1*k(4)+4*k(3)*k(1)+3*k(2)^2+6*k(2)*k(1)^2+1*k(1)^4 and T(4,4)=6 since there are six ways of partitioning four labeled items into one part with two items and two parts each with one item.
		

References

• See A036040 for the column labeled "M_3" in Abramowitz and Stegun, Handbook, p. 831.

Links

• Alois P. Heinz, Rows n = 1..26, flattened
• M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
• Berg, Kimmo Complexity of solution structures in nonlinear pricing, Ann. Oper. Res. 206, 23-37 (2013).
• R. J. Cano, Sequencer program.
• Mark W. Coffey, A Set of Identities for a Class of Alternating Binomial Sums Arising in Computing Applications, arXiv:math-ph/0608049, 2006.
• Wikipedia, Cumulant.
• Wikipedia, Bell polynomials

Crossrefs

See A036040 for another version. Cf. A036036-A036039.

Row sums are A000110.

Row lengths are A000041.

Cf. A007446. - Tilman Neumann, Oct 05 2008

Cf. A178866 and A178867 (version 3). - Johannes W. Meijer, Jun 21 2010

Maximum value in row n gives A102356(n).

Programs

Mathematica

runs[li:{__Integer}] := ((Length/@ Split[ # ]))&[Sort@ li]; Table[Apply[Multinomial, IntegerPartitions[w], {1}]/Apply[Times, (runs/@ IntegerPartitions[w])!, {1}], {w, 6}]
(* Second program: *)
completeBellMatrix[x_, n_] := Module[{M, i, j}, M[, ] = 0; For[i=1, i <= n-1 , i++, M[i, i+1] = -1]; For[i=1, i <= n , i++, For[j=1, j <= i, j++, M[i, j] = Binomial[i-1, j-1]*x[i-j+1]]]; Array[M, {n, n}]]; completeBellPoly[x_, n_] := Det[completeBellMatrix[x, n]]; row[n_] := List @@ completeBellPoly[x, n] /. x[] -> 1 // Reverse; Table[row[n], {n, 1, 10}] // Flatten (* _Jean-François Alcover, Aug 31 2016, after Tilman Neumann *)
B[0] = 1;
B[n_] := B[n] = Sum[Binomial[n-1, k] B[n-k-1] x[k+1], {k, 0, n-1}]//Expand;
row[n_] := Reverse[List @@ B[n] /. x[_] -> 1];
Table[row[n], {n, 1, 10}] // Flatten (* Jean-François Alcover, Aug 10 2018, after Wolfdieter Lang *)

MuPAD

completeBellMatrix := proc(x,n) // x - vector x[1]...x[m], m>=n
local i,j,M; begin M:=matrix(n,n): // zero-initialized
for i from 1 to n-1 do M[i,i+1]:=-1: end_for:
for i from 1 to n do for j from 1 to i do
    M[i,j] := binomial(i-1,j-1)*x[i-j+1]:
end_for: end_for:
return (M): end_proc:
completeBellPoly := proc(x, n) begin
return (linalg::det(completeBellMatrix(x,n))): end_proc:
for i from 1 to 10 do print(i,completeBellPoly(x,i)): end_for:
// Tilman Neumann, Oct 05 2008

PARI

\\ See links.

PARI

A080575_poly(n,V=vector(n,i,eval(Str('x,i))))={matdet(matrix(n,n,i,j,if(j<=i,binomial(i-1,j-1)*V[n-i+j],-(j==i+1))))}
A080575_row(n)={(f(s)=if(type(s)!="t_INT",concat(apply(f,select(t->t,Vec(s)))),s))(A080575_poly(n))} \\ M. F. Hasler, Jul 12 2015