cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A183109 Triangle read by rows: T(n,m) = number of n X m binary matrices with no zero rows or columns (n >= 1, 1 <= m <= n).

Original entry on oeis.org

1, 1, 7, 1, 25, 265, 1, 79, 2161, 41503, 1, 241, 16081, 693601, 24997921, 1, 727, 115465, 10924399, 831719761, 57366997447, 1, 2185, 816985, 167578321, 26666530801, 3776451407065, 505874809287625
Offset: 1

Views

Author

Steffen Eger, Feb 01 2011

Keywords

Comments

T(n,m) = T(m,n) is also the number of complete alignments between two strings of sizes m and n, respectively; i.e. the number of complete matchings in a bipartite graph
From Manfred Boergens, Jul 25 2021: (Start)
The matrices in the definition are a superset of the matrices in the comment to A019538 by Manfred Boergens.
T(n,m) is the number of coverings of [n] by tuples (A_1,...,A_m) in P([n])^m with nonempty A_j, with P(.) denoting the power set (corrected for clarity by Manfred Boergens, May 26 2024). For the disjoint case see A019538.
For tuples with "nonempty" dropped see A092477 and A329943 (amendment by Manfred Boergens, Jun 24 2024). (End)

Examples

			Triangle begins:
  1;
  1,    7;
  1,   25,    265;
  1,   79,   2161,     41503;
  1,  241,  16081,    693601,    24997921;
  1,  727, 115465,  10924399,   831719761,   57366997447;
  1, 2185, 816985, 167578321, 26666530801, 3776451407065, 505874809287625;
  ...
		

Crossrefs

Cf. A218695 (same sequence with restriction m<=n dropped).
Cf. A058482 (this gives the general formula, but values only for m=3).
Main diagonal gives A048291.
Column 2 is A058481.

Programs

  • Maple
    A183109 := proc(n,m)
        add((-1)^j*binomial(m,j)*(2^(m-j)-1)^n,j=0..m) ;
    end proc:
    seq(seq(A183109(n,m),m=1..n),n=1..10) ; # R. J. Mathar, Dec 03 2015
  • Mathematica
    Flatten[Table[Sum[ (-1)^j*Binomial[m, j]*(2^(m - j) - 1)^n, {j, 0, m}], {n, 1, 7}, {m, 1, n}]] (* Indranil Ghosh, Mar 14 2017 *)
  • PARI
    tabl(nn) = {for(n=1, nn, for(m = 1, n, print1(sum(j=0, m, (-1)^j*binomial(m, j)*(2^(m - j) - 1)^n),", ");); print(););};
    tabl(8); \\ Indranil Ghosh, Mar 14 2017
    
  • Python
    import math
    f = math.factorial
    def C(n,r): return f(n)//f(r)//f(n - r)
    def T(n,m):
        return sum((-1)**j*C(m,j)*(2**(m - j) - 1)**n for j in range (m+1))
    i=1
    for n in range(1,21):
        for m in range(1, n+1):
            print(str(i)+" "+str(T(n, m)))
            i+=1 # Indranil Ghosh, Mar 14 2017

Formula

T(n,m) = Sum_{j=0..m}(-1)^j*C(m, j)*(2^(m-j)-1)^n.
Recursion: T(m,n) = Sum_{k=1..m} T(k,n-1)*C(m,k)*2^k - T(m,n-1).
From Robert FERREOL, Mar 14 2017: (Start)
T(n,m) = Sum_{i = 0 .. n,j = 0 ..m}(-1)^(n+m+i+j)*C(n,i)*C(m,j)*2^(i*j).
Inverse formula of: 2^(n*m) = Sum_{i = 0 .. n , j = 0 ..m} C(n,i)*C(m,j)*T(i,j). (End)
A019538(j) <= a(j). - Manfred Boergens, Jul 25 2021

A054780 Number of n-covers of a labeled n-set.

Original entry on oeis.org

1, 1, 3, 32, 1225, 155106, 63602770, 85538516963, 386246934638991, 6001601072676524540, 327951891446717800997416, 64149416776011080449232990868, 45546527789182522411309599498741023, 118653450898277491435912500458608964207578
Offset: 0

Views

Author

Vladeta Jovovic, May 21 2000

Keywords

Comments

Also, number of n X n rational {0,1}-matrices with no zero rows or columns and with all rows distinct, up to permutation of rows.

Examples

			From _Gus Wiseman_, Dec 19 2023: (Start)
Number of ways to choose n nonempty sets with union {1..n}. For example, the a(3) = 32 covers are:
  {1}{2}{3}  {1}{2}{13}  {1}{2}{123}  {1}{12}{123}  {12}{13}{123}
             {1}{2}{23}  {1}{3}{123}  {1}{13}{123}  {12}{23}{123}
             {1}{3}{12}  {1}{12}{13}  {1}{23}{123}  {13}{23}{123}
             {1}{3}{23}  {1}{12}{23}  {2}{12}{123}
             {2}{3}{12}  {1}{13}{23}  {2}{13}{123}
             {2}{3}{13}  {2}{3}{123}  {2}{23}{123}
                         {2}{12}{13}  {3}{12}{123}
                         {2}{12}{23}  {3}{13}{123}
                         {2}{13}{23}  {3}{23}{123}
                         {3}{12}{13}  {12}{13}{23}
                         {3}{12}{23}
                         {3}{13}{23}
(End)
		

Crossrefs

Main diagonal of A055154.
Covers with any number of edges are counted by A003465, unlabeled A055621.
Connected graphs of this type are counted by A057500, unlabeled A001429.
This is the covering case of A136556.
The case of graphs is A367863, covering case of A116508, unlabeled A006649.
Binomial transform is A367916.
These set-systems have ranks A367917.
The unlabeled version is A368186.
A006129 counts covering graphs, connected A001187, unlabeled A002494.
A046165 counts minimal covers, ranks A309326.

Programs

  • Mathematica
    Join[{1}, Table[Sum[StirlingS1[n+1, k+1]*(2^k - 1)^n, {k, 0, n}]/n!, {n, 1, 15}]] (* Vaclav Kotesovec, Jun 04 2022 *)
    Table[Length[Select[Subsets[Rest[Subsets[Range[n]]],{n}],Union@@#==Range[n]&]],{n,0,4}] (* Gus Wiseman, Dec 19 2023 *)
  • PARI
    a(n) = sum(k=0, n, (-1)^k*binomial(n, k)*binomial(2^(n-k)-1, n)) \\ Andrew Howroyd, Jan 20 2024

Formula

a(n) = Sum_{k=0..n} (-1)^k*binomial(n, k)*binomial(2^(n-k)-1, n).
a(n) = (1/n!)*Sum_{k=0..n} Stirling1(n+1, k+1)*(2^k-1)^n.
G.f.: Sum_{n>=0} log(1+(2^n-1)*x)^n/((1+(2^n-1)*x)*n!). - Paul D. Hanna and Vladeta Jovovic, Jan 16 2008
a(n) ~ 2^(n^2) / n!. - Vaclav Kotesovec, Jun 04 2022
Inverse binomial transform of A367916. - Gus Wiseman, Dec 19 2023

A057150 Triangle read by rows: T(n,k) = number of k X k binary matrices with n ones, with no zero rows or columns, up to row and column permutation.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 2, 1, 0, 0, 5, 2, 1, 0, 0, 4, 11, 2, 1, 0, 0, 3, 21, 14, 2, 1, 0, 0, 1, 34, 49, 15, 2, 1, 0, 0, 1, 33, 131, 69, 15, 2, 1, 0, 0, 0, 33, 248, 288, 79, 15, 2, 1, 0, 0, 0, 19, 410, 840, 420, 82, 15, 2, 1, 0, 0, 0, 14, 531, 2144, 1744, 497, 83, 15, 2, 1
Offset: 1

Views

Author

Vladeta Jovovic, Aug 14 2000

Keywords

Comments

Also the number of non-isomorphic set multipartitions (multisets of sets) of weight n with k parts and k vertices. - Gus Wiseman, Nov 14 2018

Examples

			[1], [0,1], [0,1,1], [0,1,2,1], [0,0,5,2,1], [0,0,4,11,2,1], ...;
There are 8 square binary matrices with 5 ones, with no zero rows or columns, up to row and column permutation: 5 of size 3 X 3:
[0 0 1] [0 0 1] [0 0 1] [0 0 1] [0 0 1]
[0 0 1] [0 1 0] [0 1 1] [0 1 1] [1 1 0]
[1 1 1] [1 1 1] [1 0 1] [1 1 0] [1 1 0]
2 of size 4 X 4:
[0 0 0 1] [0 0 0 1]
[0 0 0 1] [0 0 1 0]
[0 0 1 0] [0 1 0 0]
[1 1 0 0] [1 0 0 1]
and 1 of size 5 X 5:
[0 0 0 0 1]
[0 0 0 1 0]
[0 0 1 0 0]
[0 1 0 0 0]
[1 0 0 0 0].
From _Gus Wiseman_, Nov 14 2018: (Start)
Triangle begins:
   1
   0   1
   0   1   1
   0   1   2   1
   0   0   5   2   1
   0   0   4  11   2   1
   0   0   3  21  14   2   1
   0   0   1  34  49  15   2   1
   0   0   1  33 131  69  15   2   1
   0   0   0  33 248 288  79  15   2   1
Non-isomorphic representatives of the multiset partitions counted in row 6 {0,0,4,11,2,1} are:
  {{12}{13}{23}}  {{1}{1}{1}{234}}  {{1}{2}{3}{3}{45}}  {{1}{2}{3}{4}{5}{6}}
  {{1}{23}{123}}  {{1}{1}{24}{34}}  {{1}{2}{3}{5}{45}}
  {{13}{23}{23}}  {{1}{1}{4}{234}}
  {{3}{23}{123}}  {{1}{2}{34}{34}}
                  {{1}{3}{24}{34}}
                  {{1}{3}{4}{234}}
                  {{1}{4}{24}{34}}
                  {{1}{4}{4}{234}}
                  {{2}{4}{12}{34}}
                  {{3}{4}{12}{34}}
                  {{4}{4}{12}{34}}
(End)
		

Crossrefs

Programs

  • Mathematica
    permcount[v_List] := Module[{m = 1, s = 0, k = 0, t}, For[i = 1, i <= Length[v], i++, t = v[[i]]; k = If[i > 1 && t == v[[i - 1]], k + 1, 1]; m *= t*k; s += t]; s!/m];
    c[p_List, q_List, k_] := SeriesCoefficient[Product[Product[(1 + O[x]^(k + 1) + x^LCM[p[[i]], q[[j]]])^GCD[p[[i]], q[[j]]], {j, 1, Length[q]}], {i, 1, Length[p]}], {x, 0, k}];
    M[m_, n_, k_] := M[m, n, k] = Module[{s = 0}, Do[Do[s += permcount[p]* permcount[q]*c[p, q, k], {q, IntegerPartitions[n]}], {p, IntegerPartitions[m]}]; s/(m!*n!)];
    T[n_, k_] := M[k, k, n] - 2*M[k, k - 1, n] + M[k - 1, k - 1, n];
    Table[T[n, k], {n, 1, 12}, {k, 1, n}] // Flatten (* Jean-François Alcover, Sep 10 2019, after Andrew Howroyd *)
  • PARI
    \\ See A321609 for M.
    T(n,k) = M(k,k,n) - 2*M(k,k-1,n) + M(k-1,k-1,n); \\ Andrew Howroyd, Nov 14 2018

Extensions

Duplicate seventh row removed by Gus Wiseman, Nov 14 2018

A262307 Array read by antidiagonals: T(m,n) = number of m X n binary matrices with all 1's connected and no zero rows or columns.

Original entry on oeis.org

1, 1, 1, 1, 5, 1, 1, 19, 19, 1, 1, 65, 205, 65, 1, 1, 211, 1795, 1795, 211, 1, 1, 665, 14221, 36317, 14221, 665, 1, 1, 2059, 106819, 636331, 636331, 106819, 2059, 1, 1, 6305, 778765, 10365005, 23679901, 10365005, 778765, 6305, 1
Offset: 1

Views

Author

N. J. A. Sloane, Oct 04 2015

Keywords

Comments

Two 1's are connected if they are in the same row or column. The requirement is for them to form a single connected set.
The number of m X n binary matrices with no zero rows or columns is given by A183109(m, n). If there are multiple components (not connected) then they cannot share either rows or columns. For i < n and j < m there are T(i,j) ways of creating an i X j component that occupies the first row. Its remaining i-1 rows may be on any of the remaining m-1 rows with its j columns on any of the n columns. The m-i rows and n-j columns not used by this component can be any matrix with no zero rows or columns.
T(m,n) is also the number of bipartite connected labeled graphs with parts of size m and n. (See A005333, A227322.)
This is the array a(m,n) in Kreweras (1969). Kreweras describes this as a symmetric triangle read by rows, giving numbers of connected relations.
The companion array b(m,n) (and the first few of its diagonals) in Kreweras (1969) should also be added to the OEIS if they are not already present.

Examples

			Table starts:
==========================================================================
m\n| 1    2      3         4           5             6               7
---|----------------------------------------------------------------------
1  | 1    1      1         1           1             1               1 ...
2  | 1    5     19        65         211           665            2059 ...
3  | 1   19    205      1795       14221        106819          778765 ...
4  | 1   65   1795     36317      636331      10365005       162470155 ...
5  | 1  211  14221    636331    23679901     805351531     26175881341 ...
6  | 1  665 106819  10365005   805351531   56294206205   3735873535339 ...
7  | 1 2059 778765 162470155 26175881341 3735873535339 502757743028605 ...
...
As a triangle, this begins:
  1;
  1,    1;
  1,    5,      1;
  1,   19,     19,      1;
  1,   65,    205,     65,      1;
  1,  211,   1795,   1795,    211,      1;
  1,  665,  14221,  36317,  14221,    665,    1;
  1, 2059, 106819, 636331, 636331, 106819, 2059, 1;
  ...
		

Crossrefs

Essentially same table as triangle A227322 (where the antidiagonals only go halfway).
Main diagonal is A005333.
Initial diagonals give A001047, A002501, A002502.

Programs

  • Mathematica
    A183109[n_, m_] := Sum[(-1)^j*Binomial[m, j]*(2^(m-j) - 1)^n, {j, 0, m}];
    T[m_, n_] := A183109[m, n] - Sum[T[i, j]*A183109[m - i, n - j] Binomial[m - 1, i - 1]*Binomial[n, j], {i, 1, m - 1}, {j, 1, n - 1}];
    Table[T[m - n + 1, n], {m, 1, 9}, {n, 1, m}] // Flatten (* Jean-François Alcover, Oct 08 2017, after Andrew Howroyd *)
  • PARI
    G(N)={my(S=matrix(N,N), T=matrix(N,N));
    for(m=1,N,for(n=1,N,
    S[m,n]=sum(j=0, m, (-1)^j*binomial(m, j)*(2^(m - j) - 1)^n);
    T[m,n]=S[m,n]-sum(i=1, m-1, sum(j=1, n-1, T[i,j]*S[m-i,n-j]*binomial(m-1,i-1)*binomial(n,j)));
    ));T}
    G(7) \\ Andrew Howroyd, May 22 2017

Formula

T(m,n) = A183109(m,n) - Sum_{i=1..m-1} Sum_{j=1..n-1} T(i,j)*A183109(m-i, n-j)*binomial(m-1,i-1)*binomial(n,j). - Andrew Howroyd, May 22 2017

Extensions

Revised by N. J. A. Sloane, May 26 2017, to incorporate material from Andrew Howroyd's May 22 2017 submission (formerly A287297), which was essentially identical to this, although giving an alternative description and more information.

A104601 Triangle T(r,n) read by rows: number of n X n (0,1)-matrices with exactly r entries equal to 1 and no zero row or columns.

Original entry on oeis.org

1, 0, 2, 0, 4, 6, 0, 1, 45, 24, 0, 0, 90, 432, 120, 0, 0, 78, 2248, 4200, 720, 0, 0, 36, 5776, 43000, 43200, 5040, 0, 0, 9, 9066, 222925, 755100, 476280, 40320, 0, 0, 1, 9696, 727375, 6700500, 13003620, 5644800, 362880, 0, 0, 0, 7480, 1674840
Offset: 1

Views

Author

Ralf Stephan, Mar 27 2005

Keywords

Examples

			1
0,2
0,4,6
0,1,45,24
0,0,90,432,120
0,0,78,2248,4200,720
0,0,36,5776,43000,43200,5040
0,0,9,9066,222925,755100,476280,40320
0,0,1,9696,727375,6700500,13003620,5644800,362880
0,0,0,7480,1674840,37638036,179494350,226262400,71850240,3628800
		

Crossrefs

Right-edge diagonals include A000142, A055602, A055603. Row sums are in A104602.
Column sums are in A048291. The triangle read by columns = A055599.

Programs

  • Mathematica
    t[r_, n_] := Sum[ Sum[ (-1)^(2n - d - k/d)*Binomial[n, d]*Binomial[n, k/d]*Binomial[k, r], {d, Divisors[k]}], {k, r, n^2}]; Flatten[ Table[t[r, n], {r, 1, 10}, {n, 1, r}]] (* Jean-François Alcover, Jun 27 2012, from formula *)
    Table[Length[Select[Subsets[Tuples[Range[n],2],{n}],Union[First/@#]==Union[Last/@#]==Range[k]&]],{n,6},{k,n}] (* Gus Wiseman, Nov 14 2018 *)

Formula

T(r, n) = Sum{l>=r, Sum{d|l, (-1)^(2n-d-l/d)*C(n, d)*C(n, l/d)*C(l, r) }}.
E.g.f.: Sum(((1+x)^n-1)^n*exp((1-(1+x)^n)*y)*y^n/n!,n=0..infinity). - Vladeta Jovovic, Feb 24 2008

A086193 Number of n X n matrices with entries in {0,1} with no zero row, no zero column and with zero main diagonal.

Original entry on oeis.org

1, 0, 1, 18, 1699, 592260, 754179301, 3562635108438, 63770601591579079, 4405870283636411477640, 1190873924687350003735546441, 1270602397076493907445608866890778, 5381240610642043789096251476993474339179
Offset: 0

Views

Author

W. Edwin Clark, Aug 25 2003

Keywords

Comments

Also the number of simple labeled digraphs on n nodes for which every vertex has indegree at least one and outdegree at least one.
Also the number of edge covers on the n-crown graph. - Eric W. Weisstein, May 19 2017

Crossrefs

Cf. A048291.

Programs

  • Mathematica
    Table[ it = (Partition[ #1, n ] &) /@ IntegerDigits[ Range[ 0, -1 + 2^n^2 ], 2, n^2 ]; Count[ it, (q_)?MatrixQ /; Tr[ q ] === 0 && (Times @@ (Plus @@@ q)) > 0 && (Times @@ (Plus @@@ Transpose[ q ]) > 0) ], {n, 1, 4} ] (* Wouter Meeussen, Aug 25 2003 *)
    Table[Sum[(-1)^(n-r)*Binomial[n, r]*(2^(r-1)-1)^r*(2^r-1)^(n-r), {r,0,n}],{n,1,15}] (* Vaclav Kotesovec, May 04 2015 after Vladeta Jovovic *)
  • PARI
    a(n)={sum(r=0, n, (-1)^(n-r)*binomial(n, r)*(2^(r-1)-1)^r*(2^r-1)^(n-r))} \\ Andrew Howroyd, Sep 09 2018

Formula

a(n) = Sum_{r=0..n} (-1)^(n-r)*binomial(n, r)*(2^(r-1)-1)^r*(2^r-1)^(n-r). - Vladeta Jovovic, Aug 27 2003
a(n) = sum( f(n, r), r=0..n ) where f(n, r) = binomial(n, r) (-1)^r (1-2^(-n+r+1))^(n-r) (1-2^(-n+r))^r 2^((n-r)(n-1)). - Brendan McKay, Aug 27 2003
E.g.f.: Sum_{k>=0} (2^(n-1)-1)^n*exp((1-2^n)*x)*x^n/n!. - Vladeta Jovovic, Feb 23 2008
a(n) ~ 2^(n*(n-1)). - Vaclav Kotesovec, May 04 2015

Extensions

More terms from Brendan McKay, Aug 27 2003
a(0)=1 prepended by Andrew Howroyd, Sep 09 2018

A218695 Square array A(h,k) = (2^h-1)*A(h,k-1) + Sum_{i=1..h-1} binomial(h,h-i)*2^i*A(i,k-1), with A(1,k) = A(h,1) = 1; read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 7, 1, 1, 25, 25, 1, 1, 79, 265, 79, 1, 1, 241, 2161, 2161, 241, 1, 1, 727, 16081, 41503, 16081, 727, 1, 1, 2185, 115465, 693601, 693601, 115465, 2185, 1, 1, 6559, 816985, 10924399, 24997921, 10924399, 816985, 6559, 1
Offset: 1

Views

Author

M. F. Hasler, Nov 04 2012

Keywords

Comments

This symmetric table is defined in the Kreweras papers, used also in A223911. Its upper or lower triangular part equals A183109, which might provide a simpler formula.
Number of h X k binary matrices with no zero rows or columns. - Andrew Howroyd, Mar 29 2023
A(h,k) is the number of coverings of [h] by tuples (A_1,...,A_k) in P([h])^k with nonempty A_j, with P(.) denoting the power set. For the disjoint case see A019538. For tuples with "nonempty" omitted see A092477 and A329943 (amendment by Manfred Boergens, Jun 24 2024). - Manfred Boergens, May 26 2024

Examples

			Array A(h,k) begins:
=====================================================
h\k | 1   2      3        4         5           6 ...
----+------------------------------------------------
  1 | 1   1      1        1         1           1 ...
  2 | 1   7     25       79       241         727 ...
  3 | 1  25    265     2161     16081      115465 ...
  4 | 1  79   2161    41503    693601    10924399 ...
  5 | 1 241  16081   693601  24997921   831719761 ...
  6 | 1 727 115465 10924399 831719761 57366997447 ...
  ...
		

Crossrefs

Columns 1..3 are A000012, A058481, A058482.
Main diagonal is A048291.
Cf. A019538, A056152 (unlabeled case), A052332, A092477, A183109, A223911, A329943.

Programs

  • PARI
    c(h,k)={(h<2 || k<2) & return(1); sum(i=1,h-1,binomial(h,h-i)*2^i*c(i,k-1))+(2^h-1)*c(h,k-1)}
    /* For better performance when h and k are large, insert the following memoization code before "sum(...)": cM=='cM & cM=matrix(h,k); my(s=matsize(cM));
    s[1] >= h & s[2] >= k & cM[h,k] & return(cM[h,k]);
    s[1]
    				
  • PARI
    A(m, n) = sum(k=0, m, (-1)^(m-k) * binomial(m, k) * (2^k-1)^n ) \\ Andrew Howroyd, Mar 29 2023

Formula

From Andrew Howroyd, Mar 29 2023: (Start)
A(h, k) = Sum_{i=0..h} (-1)^(h-i) * binomial(h, i) * (2^i-1)^k.
A052332(n) = Sum_{i=1..n-1} binomial(n,i)*A(i, n-i) for n > 0. (End)

A287065 Number of dominating sets on the n X n rook graph.

Original entry on oeis.org

1, 11, 421, 59747, 32260381, 67680006971, 559876911043381, 18412604442711949187, 2416403019417984915336061, 1267413006543912045144741284411, 2658304092145691708492995820522716981, 22300364428188338185156192161829091442585827
Offset: 1

Views

Author

Eric W. Weisstein, May 19 2017

Keywords

Comments

Number of {0,1} n X n matrices with no zero rows or no zero columns. - Geoffrey Critzer, Jan 15 2024

Crossrefs

Main diagonal of A287274.
Row sums of A368831.

Programs

  • Mathematica
    Table[(2^n - 1)^n + Sum[Binomial[n, i] Sum[(-1)^j (-1 + 2^(n - j))^i Binomial[n, j], {j, 0, n}], {i, n - 1}], {n, 20}] (* Eric W. Weisstein, May 27 2017 *)
  • PARI
    b(m,n)=sum(j=0, m, (-1)^j*binomial(m, j)*(2^(m - j) - 1)^n);
    a(n)=(2^n-1)^n + sum(i=1,n-1,b(n,i)*binomial(n,i)); \\ Andrew Howroyd, May 22 2017

Formula

a(n) = (2^n-1)^n + Sum_{i=1..n-1} binomial(n,i) * A183109(n,i). - Andrew Howroyd, May 22 2017

Extensions

a(6)-a(12) from Andrew Howroyd, May 22 2017

A055599 Triangle T(n,k) read by rows, giving the number of n X n binary matrices with no zero rows or columns and with k=0..n^2 ones.

Original entry on oeis.org

0, 1, 0, 0, 2, 4, 1, 0, 0, 0, 6, 45, 90, 78, 36, 9, 1, 0, 0, 0, 0, 24, 432, 2248, 5776, 9066, 9696, 7480, 4272, 1812, 560, 120, 16, 1, 0, 0, 0, 0, 0, 120, 4200, 43000, 222925, 727375, 1674840, 2913100, 3995100, 4441200, 4073100, 3114140, 1994550
Offset: 1

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Author

Vladeta Jovovic, Jun 01 2000

Keywords

Comments

Rows also give the coefficients of the edge cover polynomials of the complete bipartite graph K_{n,n}. - Eric W. Weisstein, Apr 24 2017

Examples

			For m=n=3 we get T(3,k)=C(9,k)-6*C(6,k)+9*C(4,k)+6*C(3,k)-18*C(2,k)+9*C(1,k)-C(0,k) giving the batch [0,0,0,6,45,90,78,36,9,1].
Triangle begins:
0, 1,
0, 0, 2, 4, 1,
0, 0, 0, 6, 45, 90, 78, 36, 9, 1,
0, 0, 0, 0, 24, 432, 2248, 5776, 9066, 9696, 7480, 4272, 1812, 560, 120, 16, 1,
...
		

Crossrefs

Cf. A048291 (row sums).

Programs

  • Mathematica
    row[n_] := Sum[(-1)^(n-k) Binomial[n, k] ((1+x)^k - 1)^n, {k, 0, n}] + O[x]^(n^2+1) // CoefficientList[#, x]&;
    Table[row[n], {n, 1, 5}] // Flatten (* Jean-François Alcover, Nov 06 2018 *)

Formula

Number of m X n binary matrices with no zero rows or columns and with k=0..m*n ones is Sum_{i=0..n} (-1)^i*C(n, i)*a(m, n-i, k) where a(m, n, k)=Sum_{i=0..m} (-1)^i*C(m, i)*C((m-i)*n, k).
G.f. for n-th row: Sum_{k=0..n} (-1)^(n-k)*binomial(n, k)*((1+x)^k-1)^n. - Vladeta Jovovic, Apr 04 2003
E.g.f.: Sum(((1+y)^n-1)^n*exp((1-(1+y)^n)*x)*x^n/n!,n=0..infinity). - Vladeta Jovovic, Feb 24 2008

A055084 Number of 6 X n binary matrices with no zero rows or columns, up to row and column permutation.

Original entry on oeis.org

1, 15, 180, 2001, 20755, 200082, 1781941, 14637962, 111011667, 779695050, 5093379110, 31092553357, 178203364143, 963217652830, 4930357535218, 23989343505296, 111335037107474, 494383391324356, 2106346854756098
Offset: 1

Views

Author

Vladeta Jovovic, Jun 13 2000

Keywords

Crossrefs

Column k=6 of A056152.

Programs

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