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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A058001 Number of 3 X 3 matrices with entries mod n, up to row and column permutation.

Original entry on oeis.org

1, 36, 738, 8240, 57675, 289716, 1144836, 3780288, 10865205, 27969700, 65834406, 143887536, 295467263, 575308020, 1069960200, 1911933696, 3298486761, 5516122788, 8972008810, 14233690800, 22078652211, 33555443636, 50058302988, 73417387200, 106006948125
Offset: 1

Views

Author

Vladeta Jovovic, Nov 04 2000

Keywords

Comments

Number of k X l matrices with entries mod n, up to row and column permutation is Z(S_k X S_l; n,n,...) where Z(S_k X S_l; x_1,x_2,...) is cycle index of Cartesian product of symmetric groups S_k and S_l of degree k and l, respectively.

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[x (12x^7+369x^6+2514x^5+4375x^4+2360x^3+423x^2+26x+1)/(x-1)^10,{x,0,30}],x] (* or *) LinearRecurrence[{10,-45,120,-210,252,-210,120,-45,10,-1},{0,1,36,738,8240,57675,289716,1144836,3780288,10865205},30] (* Harvey P. Dale, Nov 23 2024 *)

Formula

a(n) = (1/3!^2)*(n^9 + 6*n^6 + 9*n^5 + 8*n^3 + 12*n^2).
G.f.: x*(12*x^7+369*x^6+2514*x^5+4375*x^4+2360*x^3+423*x^2+26*x+1) / (x-1)^10. - Colin Barker, Jul 09 2013

A058004 Number of 6 X 6 matrices with entries mod n, up to row and column permutation.

Original entry on oeis.org

1, 251610, 302752867740, 9178323524804624, 28125393244553141210, 19909522361922032493690, 5116530046996205504668323, 626072069382507442113224128, 43460016875695276108491159279
Offset: 1

Views

Author

Vladeta Jovovic, Nov 04 2000

Keywords

Comments

Number of k X l matrices with entries mod n, up to row and column permutation is Z(S_k X S_l; n,n,...) where Z(S_k X S_l; x_1,x_2,...) is cycle index of Cartesian product of symmetric groups S_k and S_l of degree k and l, respectively.

Crossrefs

Formula

a(n)=(1/6!^2)*(n^36 + 30*n^30 + 225*n^26 + 170*n^24 + 1350*n^22 + 3225*n^20 + 4075*n^18 + 9900*n^16 + 28500*n^14 + 56048*n^12 + 61020*n^10 + 77616*n^8 + 153840*n^6 + 87840*n^4 + 34560*n^2).

A058003 Number of 5 X 5 matrices with entries mod n, up to row and column permutation.

Original entry on oeis.org

1, 5624, 64796982, 79846389608, 20834113243925, 1979525296377132, 93242242505023122, 2625154125717590496, 49871029909245781491, 694584034909225304800, 7525039263469551291908, 66252712846754819753160
Offset: 1

Views

Author

Vladeta Jovovic, Nov 04 2000

Keywords

Comments

Number of k X l matrices with entries mod n, up to row and column permutation is Z(S_k X S_l; n,n,...) where Z(S_k X S_l; x_1,x_2,...) is cycle index of Cartesian product of symmetric groups S_k and S_l of degree k and l, respectively.

Crossrefs

Formula

a(n)=(1/5!^2)*(n^25 + 20*n^20 + 100*n^17 + 70*n^15 + 300*n^14 + 225*n^13 + 400*n^12 + 400*n^11 + 100*n^10 + 1600*n^9 + 2300*n^8 + 1300*n^7 + 1200*n^6 + 1824*n^5 + 480*n^4 + 1680*n^3 + 2400*n^2).

Extensions

More terms from James Sellers, Nov 08 2000

A242106 Number T(n,k) of inequivalent n X n matrices using exactly k different symbols, where equivalence means permutations of rows or columns or the symbol set; triangle T(n,k), n>=0, 0<=k<=n^2, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 4, 3, 1, 0, 1, 17, 121, 269, 241, 100, 24, 3, 1, 0, 1, 172, 15239, 316622, 1951089, 4820228, 5769214, 3768929, 1451594, 347251, 53628, 5645, 451, 37, 3, 1, 0, 1, 2811, 10802952, 3316523460, 170309112972, 2577666563670, 15839885888526
Offset: 0

Views

Author

Alois P. Heinz, Aug 15 2014

Keywords

Comments

Note that the sequence with very similar number A246106 is related but different! - M. F. Hasler, Apr 29 2022

Examples

			T(2,2) = 4:
  [1 0]  [1 1]  [1 0]  [1 0]
  [0 0], [0 0], [1 0], [0 1].
Triangle T(n,k) begins:
  1;
  0, 1;
  0, 1, 4, 3, 1;
  0, 1, 17, 121, 269, 241, 100, 24, 3, 1;
  0, 1, 172, 15239, 316622, 1951089, 4820228, 5769214, 3768929, ...
  0, 1, 2811, 10802952, 3316523460, 170309112972, 2577666563670, ...
  0, 1, 126445, 50459558944, 382379913244053, 233995925116415261, ...
		

Crossrefs

Row sums give A091057.
Main diagonal gives A360664.

Programs

  • Maple
    with(numtheory):
    b:= proc(n, i) option remember; `if`(n=0, {0}, `if`(i<1, {},
          {seq(map(p-> p+j*x^i, b(n-i*j, i-1) )[], j=0..n/i)}))
        end:
    A:= proc(n, k) option remember; add(add(add(mul(mul(add(d*
          coeff(u, x, d), d=divisors(ilcm(i, j)))^(igcd(i, j)*
          coeff(s, x, i)*coeff(t, x, j)), j=1..degree(t)),
          i=1..degree(s))/mul(i^coeff(u, x, i)*coeff(u, x, i)!,
          i=1..degree(u))/mul(i^coeff(t, x, i)*coeff(t, x, i)!,
          i=1..degree(t))/mul(i^coeff(s, x, i)*coeff(s, x, i)!,
          i=1..degree(s)), u=b(k$2)), t=b(n$2)), s=b(n$2))
        end:
    T:= (n, k)-> A(n, k) -A(n, k-1):
    seq(seq(T(n, k), k=0..n^2), n=0..4);
  • Mathematica
    Unprotect[Power]; 0^0 = 1; Protect[Power]; b[n_, i_] := b[n, i] = If[n == 0, {0}, If[i<1, {}, Table[Map[Function[{p}, p+j*x^i], b[n-i*j, i-1]], {j, 0, n/i}] // Flatten]]; A[n_, k_] := A[n, k] = Sum[ Sum[ Sum[ Product[ Product[ Sum[d* Coefficient[u, x, d], {d, Divisors[LCM[i, j]]}]^(GCD[i, j]*Coefficient[s, x, i] * Coefficient[t, x, j]), {j, 1, Exponent[t, x]}], {i, 1, Exponent[s, x]}] / Product[ i^Coefficient[u, x, i]*Coefficient[u, x, i]!, {i, 1, Exponent[u, x]}] / Product[ i^Coefficient[t, x, i]*Coefficient[t, x, i]!, {i, 1, Exponent[t, x]}] / Product[ i^Coefficient[s, x, i]*Coefficient[s, x, i]!, {i, 1, Exponent[s, x]}], {u, b[k, k]}], {t, b[n, n]}], {s, b[n, n]}]; T[n_, k_] := A[n, k] - A[n, k-1]; Table[ Table[T[n, k], {k, 0, n^2}], {n, 0, 4}] // Flatten (* Jean-François Alcover, Feb 13 2015, after Alois P. Heinz *)

Formula

T(n,k) = A242095(n,k) - A242095(n,k-1) for k>0. T(n,0) = A242095(n,0).

A321609 Array read by antidiagonals: T(n,k) is the number of inequivalent binary n X n matrices with k ones, under row and column permutations.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 3, 1, 1, 0, 0, 1, 3, 1, 1, 0, 0, 1, 6, 3, 1, 1, 0, 0, 0, 7, 6, 3, 1, 1, 0, 0, 0, 7, 16, 6, 3, 1, 1, 0, 0, 0, 6, 21, 16, 6, 3, 1, 1, 0, 0, 0, 3, 39, 34, 16, 6, 3, 1, 1, 0, 0, 0, 1, 44, 69, 34, 16, 6, 3, 1, 1, 0, 0, 0, 1, 55, 130, 90, 34, 16, 6, 3, 1, 1
Offset: 0

Views

Author

Andrew Howroyd, Nov 14 2018

Keywords

Examples

			Array begins:
==========================================================
n\k| 0  1  2  3  4  5  6   7   8    9   10    11    12
---+------------------------------------------------------
0  | 1  0  0  0  0  0  0   0   0    0    0     0     0 ...
1  | 1  1  0  0  0  0  0   0   0    0    0     0     0 ...
2  | 1  1  3  1  1  0  0   0   0    0    0     0     0 ...
3  | 1  1  3  6  7  7  6   3   1    1    0     0     0 ...
4  | 1  1  3  6 16 21 39  44  55   44   39    21    16 ...
5  | 1  1  3  6 16 34 69 130 234  367  527   669   755 ...
6  | 1  1  3  6 16 34 90 182 425  870 1799  3323  5973 ...
7  | 1  1  3  6 16 34 90 211 515 1229 2960  6893 15753 ...
8  | 1  1  3  6 16 34 90 211 558 1371 3601  9209 24110 ...
9  | 1  1  3  6 16 34 90 211 558 1430 3825 10278 28427 ...
...
		

Crossrefs

Rows n=6..8 are A052370, A053304, A053305.
Main diagonal is A049311.
Row sums are A002724.
Cf. A052371 (as triangle), A057150, A246106, A318795.

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_] := Module[{s = 0}, Do[Do[s += permcount[p]*permcount[q]*c[p, q, k], {q, IntegerPartitions[n]}], {p, IntegerPartitions[m]}]; s/(m!*n!)]
    Table[M[n - k, n - k, k], {n, 0, 12}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Sep 10 2019, after Andrew Howroyd *)
  • PARI
    permcount(v) = {my(m=1, s=0, k=0, t); for(i=1, #v, t=v[i]; k=if(i>1&&t==v[i-1], k+1, 1); m*=t*k; s+=t); s!/m}
    c(p, q, k)={polcoef(prod(i=1, #p, prod(j=1, #q, (1 + x^lcm(p[i], q[j]) + O(x*x^k))^gcd(p[i], q[j]))), k)}
    M(m, n, k)={my(s=0); forpart(p=m, forpart(q=n, s+=permcount(p) * permcount(q) * c(p, q, k))); s/(m!*n!)}
    for(n=0, 10, for(k=0, 12, print1(M(n, n, k), ", ")); print); \\ Andrew Howroyd, Nov 14 2018

Formula

T(n,k) = T(k,k) for n > k.
T(n,k) = 0 for k > n^2.

A058002 Number of 4 X 4 matrices with entries mod n, up to row and column permutation.

Original entry on oeis.org

1, 317, 90492, 7880456, 270656150, 4947097821, 58002778967, 490172624992, 3223155968811, 17382581357725, 79840867013666, 321169288917192, 1155731257886192, 3782368364610941, 11406226119319725, 32031530635953536, 84493500676300117, 210856844364222717
Offset: 1

Views

Author

Vladeta Jovovic, Nov 04 2000

Keywords

Comments

Number of k X l matrices with entries mod n, up to row and column permutation is Z(S_k X S_l; n,n,...) where Z(S_k X S_l; x_1,x_2,...) is cycle index of Cartesian product of symmetric groups S_k and S_l of degree k and l, respectively.

Crossrefs

Formula

a(n)=(1/4!^2)*(n^16 + 12*n^12 + 36*n^10 + 67*n^8 + 160*n^6 + 204*n^4 + 96*n^2).
G.f.: -x*(x +1)*(x^14 +299*x^13 +84940*x^12 +6299584*x^11 +142482546*x^10 +1214416453*x^9 +4351647617*x^8 +6732281120*x^7 +4351647617*x^6 +1214416453*x^5 +142482546*x^4 +6299584*x^3 +84940*x^2 +299*x +1) / (x -1)^17. - Colin Barker, Jul 09 2013

Extensions

More terms from Colin Barker, Jul 09 2013

A353585 Square array T(n,k): row n lists the number of inequivalent matrices over Z/nZ, modulo permutations of rows and columns, of size r X c, 1 <= r <= c, c >= 1.

Original entry on oeis.org

1, 1, 2, 1, 3, 3, 1, 7, 6, 4, 1, 4, 27, 10, 5, 1, 13, 10, 76, 15, 6, 1, 36, 92, 20, 175, 21, 7, 1, 5, 738, 430, 35, 351, 28, 8, 1, 22, 15, 8240, 1505, 56, 637, 36, 9, 1, 87, 267, 35, 57675, 4291, 84, 1072, 45, 10, 1, 317, 5053, 1996, 70, 289716, 10528, 120, 1701, 55, 11
Offset: 1

Views

Author

M. F. Hasler, Apr 28 2022

Keywords

Comments

The array is read by falling antidiagonals.
Each row lists the number of inequivalent matrices of size 1 X 1, then 2 X 1, 2 X 2, then 3 X 1, 3 X 2, 3 X 3, etc., with coefficients in Z/nZ (or equivalently, in {1, ..., n}). See Examples for more.
Row 1 counts the zero matrices, there is only one of any size. Row 2 counts binary matrices, this is the lower triangular part of A028657, without the trivial row & column 0. (This table might have been extended with a trivial column 0 = A000012 (counting the 1 matrix of size 0) and row 0 = A000007 counting the number of r X c matrices with no entry, as done in A246106.)
The square matrices (size 1 X 1, 2 X 2, 3 X 3, ...) are counted in columns with triangular numbers, k = T(r) = r(r+1)/2 = (1, 3, 6, 10, 15, ...) = A000217.

Examples

			The table starts
   n \ k=1,  2,   3,   4,   5,   6, ...: T(n,k)
  ----+--------------------------------------
   1  |  1   1    1    1    1     1 ...
   2  |  2   3    7    4   13    36 ...
   3  |  3   6   27   10   92   738 ...
   4  |  4  10   76   20  430  8240 ...
   5  |  5  15  175   35 1505 57675 ...
  ...
Columns 2, 3 and 4, 5, 6 correspond to matrices of size 1 X 2, 2 X 2 and 1 X 3, 2 X 3, 3 X 3, respectively.
Column 4 says that there are (1, 4, 10, 20, 35, ...) inequivalent matrices of size 1 X 3 with entries in Z/nZ (n = 1, 2, 3, 4, ...); these numbers are given by (n+2 choose 3) = binomial(n+2, 3) = n(n+1)(n+2)/6 = A000292(n).
		

Crossrefs

All of the following related sequences can be expressed in terms of T(n, k, r) := T(n, k(k-1)/2 + r), WLOG r <= k:
A028657(n,k) = A353585(2,n,k): inequivalent m X n binary matrices,
A002723(n) = T(2,n,2): size n X 2, A002724(n) = T(2,n,n): size n X n,
A002727(n) = T(2,n,3): size n X 3, A002725(n) = T(2,n,n+1): size n X (n+1),
A006148(n) = T(2,n,4): size n X 4, A002728(n) = T(2,n,n+2): size n X (n+2),
A052264(n) = T(2,n,5): size n X 5,
A052269(n) = T(3,n,n): number of inequivalent ternary matrices of size n X n,
A052271(n) = T(4,n,n): number of inequivalent matrices over Z/4Z of size n X n,
A052272(n) = T(5,n,n): number of inequivalent matrices over Z/5Z of size n X n,
A246106(n,k) = A353585(k,n,n): number of inequivalent n X n matrices over Z/kZ, and its diagonal A091058 and columns 1, 2, ..., 10: A000012, A091059, A091060, A091061, A091062, A246122, A246123, A246124, A246125, A246126.

Programs

  • PARI
    A353585(n,k,r)={if(!r,r=sqrtint(8*k)\/2; k-=r*(r-1)\2); my(m(c, p=1, L=0)=for(i=1,#c, if(i==#c || c[i+1]!=c[i], p *= c[i]^(i-L)*(i-L)!; L=i )); p, S=0); forpart(P=k, my(T=0); forpart(Q=r, T += n^sum(i=1,#P, sum(j=1,#Q, gcd(P[i],Q[j]) ))/m(Q)); S += T/m(P)); S}

Formula

Let k = c(c-1)/2 + r, 1 <= r <= c, then
T(n, c, r) := T(n, k) = Sum_{p in P(c), q in P(r)} n^S(p, q)/(N(p)*N(q)), where P(r) are the partitions of r, S(p, q) = Sum_{i in p, j in q} gcd(i, j), N(p) = Product_{distinct parts x in p} x^m(x)*m(x)!, m(x) = multiplicity of x in p.
(See, e.g., A080577 for a list of partitions of positive integers.)
In particular:
T(n, 1) = n, T(n, 2) = n(n+1)/2 = A000217(n), T(n, 4) = C(n+2, 3) = A000292(n), T(n, 7) = C(n+3, 4) = A000332(n+3), etc.: T(n, k(k+1)/2 + 1) = C(n+k, k+1),
T(n, k(k+1)/2) = A246106(k, n).

A246107 Number of inequivalent n X n matrices with entries from [n], where equivalence means permutations of rows or columns.

Original entry on oeis.org

1, 1, 7, 738, 7880456, 20834113243925, 19909522361922032493690, 10114980502439545115146468340980932, 3861175753082201291221743022346066208381644388448, 1493197587365241166689220567691206411606485768307602552950789523519
Offset: 0

Views

Author

Alois P. Heinz, Aug 13 2014

Keywords

Crossrefs

Main diagonal of A246106.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, [[]],
          `if`(i<1, [], [b(n, i-1)[], seq(map(p->[p[], [i, j]],
           b(n-i*j, i-1))[], j=1..n/i)]))
        end:
    A:= proc(n, k) option remember; add(add(k^add(add(i[2]*j[2]*
          igcd(i[1], j[1]), j=t), i=s) /mul(i[1]^i[2]*i[2]!, i=s)
          /mul(i[1]^i[2]*i[2]!, i=t), t=b(n$2)), s=b(n$2))
        end:
    a:= n-> A(n$2):
    seq(a(n), n=0..12);

Formula

a(n) = A246106(2n,n).

A256069 Number T(n,k) of inequivalent n X n matrices with entry set {1,...,k}, where equivalence means permutations of rows or columns; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 5, 0, 1, 34, 633, 0, 1, 315, 89544, 7520386, 0, 1, 5622, 64780113, 79587235420, 20435529209470, 0, 1, 251608, 302752112913, 9177112514843320, 28079504654455279395, 19740907671252532135134
Offset: 0

Views

Author

Alois P. Heinz, Mar 13 2015

Keywords

Examples

			T(2,2) = 5:
  [1 1]  [1 2]  [1 2]  [1 1]  [1 2]
  [1 2]  [2 2]  [1 2]  [2 2]  [2 1].
Triangle T(n,k) begins:
  1;
  0, 1;
  0, 1,    5;
  0, 1,   34,      633;
  0, 1,  315,    89544,     7520386;
  0, 1, 5622, 64780113, 79587235420, 20435529209470;
		

Crossrefs

Cf. A246106.
Main diagonal gives A256070.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, [[]],
          `if`(i<1, [], [b(n, i-1)[], seq(map(p->[p[], [i, j]],
           b(n-i*j, i-1))[], j=1..n/i)]))
        end:
    A:= proc(n, k) option remember; add(add(k^add(add(i[2]*j[2]*
          igcd(i[1], j[1]), j=t), i=s) /mul(i[1]^i[2]*i[2]!, i=s)
          /mul(i[1]^i[2]*i[2]!, i=t), t=b(n$2)), s=b(n$2))
        end:
    T:= (n, k)-> add(A(n, k-i)*(-1)^i*binomial(k, i), i=0..k):
    seq(seq(T(n, k), k=0..n), n=0..8);

Formula

T(n,k) = Sum_{i=0..k} (-1)^i * C(k,i) * A246106(n,k-i).

A256070 Number of inequivalent n X n matrices with entry set {1,...,n}, where equivalence means permutations of rows or columns.

Original entry on oeis.org

1, 1, 5, 633, 7520386, 20435529209470, 19740907671252532135134, 10077866175951324796988844418739012, 3855174405512686506030123555473042980898031518176, 1492231601551989489818761885384738502799149242563553845787532236092
Offset: 0

Views

Author

Alois P. Heinz, Mar 13 2015

Keywords

Examples

			a(2) = 5:
   [1 1]  [1 2]  [1 2]  [1 1]  [1 2]
   [1 2]  [2 2]  [1 2]  [2 2]  [2 1].
		

Crossrefs

Main diagonal of A256069.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, [[]],
          `if`(i<1, [], [b(n, i-1)[], seq(map(p->[p[], [i, j]],
           b(n-i*j, i-1))[], j=1..n/i)]))
        end:
    A:= proc(n, k) option remember; add(add(k^add(add(i[2]*j[2]*
          igcd(i[1], j[1]), j=t), i=s) /mul(i[1]^i[2]*i[2]!, i=s)
          /mul(i[1]^i[2]*i[2]!, i=t), t=b(n$2)), s=b(n$2))
        end:
    a:= n-> add(A(n, n-i)*(-1)^i*binomial(n, i), i=0..n):
    seq(a(n), n=0..10);

Formula

a(n) = Sum_{i=0..n} (-1)^i * C(n,i) * A246106(n,n-i).
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