A052365
Number of nonnegative integer 3 X 3 matrices with sum of elements equal to n, under row and column permutations.
Original entry on oeis.org
1, 1, 4, 10, 24, 51, 114, 219, 424, 768, 1352, 2278, 3759, 5978, 9328, 14181, 21164, 30943, 44560, 63063, 88088, 121321, 165152, 222157, 295857, 389948, 509456, 659697, 847552, 1080452, 1367814, 1719652, 2148596, 2668107, 3294676, 4046069
Offset: 0
-
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[1/Product[(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!)];
a[n_] := M[3, 3, n];
a /@ Range[0, 40] (* Jean-François Alcover, Sep 03 2019, after Andrew Howroyd in A318795 *)
A053304
Number of 7 X 7 binary matrices with n=0..49 ones up to row and column permutations.
Original entry on oeis.org
1, 1, 3, 6, 16, 34, 90, 211, 515, 1229, 2960, 6893, 15753, 34450, 72235, 143477, 269186, 473945, 781713, 1203617, 1728192, 2310376, 2874232, 3325215, 3576980, 3576980, 3325215, 2874232, 2310376, 1728192, 1203617, 781713, 473945, 269186
Offset: 0
-
\\ See A321609 for M.
vector(50, n, M(7,7,n-1))
A122082
Number of unlabeled bicolored graphs on 2n nodes which are invariant when the two color classes are interchanged.
Original entry on oeis.org
1, 2, 5, 16, 67, 404, 3904, 64840, 1930842, 104698904, 10401039400, 1900637187280, 641429385018832, 401454435464761376, 467919402404052870944, 1019758699013228238271040, 4171161230867751509749228304
Offset: 0
- R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1976.
- Andrew Howroyd, Table of n, a(n) for n = 0..50
- F. Harary, L. March and R. W. Robinson, On enumerating certain design problems in terms of bicolored graphs with no isolates, Environment and Planning, B 5 (1978), 31-43.
- F. Harary, L. March and R. W. Robinson, On enumerating certain design problems in terms of bicolored graphs with no isolates, Environment and Planning B: Urban Analytics and City Science, 5 (1978), 31-43. [Annotated scanned copy]
-
permcount[v_] := 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];
edges[v_] := Sum[GCD[v[[i]], v[[j]]], {i, 2, Length[v]}, {j, 1, i - 1}] + Total @ Quotient[v + 1, 2]
a[n_] := (s=0; Do[s += permcount[p]*2^edges[p], {p, IntegerPartitions[n]}]; s/n!);
Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Jul 06 2018, after Andrew Howroyd *)
-
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}
edges(v) = {sum(i=2, #v, sum(j=1, i-1, gcd(v[i],v[j]))) + sum(i=1, #v, (v[i]+1)\2)}
a(n) = {my(s=0); forpart(p=n, s+=permcount(p)*2^edges(p)); s/n!} \\ Andrew Howroyd, Oct 23 2017
A002725
Number of incidence matrices: n X (n+1) binary matrices under row and column permutations.
Original entry on oeis.org
1, 3, 13, 87, 1053, 28576, 2141733, 508147108, 402135275365, 1073376057490373, 9700385489355970183, 298434346895322960005291, 31479360095907908092817694945, 11474377948948020660089085281068730, 14568098446466140788730090352230460100956
Offset: 0
a(1) = 3: [0,0], [0,1], [1,1].
a(2) = 13:
000 000 000 000 001 001 001 001 001 011 011 011 111
000 001 011 111 001 010 011 110 111 011 101 111 111
- N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
- Andrew Howroyd, Table of n, a(n) for n = 0..50 (terms 0..23 from Alois P. Heinz)
- A. Kerber, Experimentelle Mathematik, Séminaire Lotharingien de Combinatoire. Institut de Recherche Math. Avancée, Université Louis Pasteur, Strasbourg, Actes 19 (1988), 77-83. [Annotated scanned copy]
- B. Misek, On the number of classes of strongly equivalent incidence matrices, (Czech with English summary) Casopis Pest. Mat. 89 1964 211-218.
-
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:= n-> add(add(2^add(add(igcd(i, j)* coeff(s, x, i)*
coeff(t, x, j), j=1..degree(t)), i=1..degree(s))/
mul(i^coeff(s, x, i)*coeff(s, x, i)!, i=1..degree(s))/
mul(i^coeff(t, x, i)*coeff(t, x, i)!, i=1..degree(t)),
t=b(n+1$2)), s=b(n$2)):
seq(a(n), n=0..12); # Alois P. Heinz, Aug 01 2014
-
b[n_, i_] := b[n, i] = If[n == 0, {0}, If[i<1, {}, Flatten @ Table[ Map[ Function[ {p}, p+j*x^i], b[n-i*j, i-1]], {j, 0, n/i}]]];
a[n_] := Sum[Sum[2^Sum[ Sum [ GCD[i, j]*Coefficient[s, x, i]*Coefficient[t, x, j], {j, 1, Exponent[t, x]}], {i, 1, Exponent[s, x]}] / Product[ i^Coefficient[s, x, i]*Coefficient[s, x, i]!, {i, 1, Exponent[s, x]}] / Product[i^Coefficient[t, x, i]*Coefficient[t, x, i]!, {i, 1, Exponent[t, x]}], {t, b[n+1, n+1]}], {s, b[n, n]}];
Table[a[n], {n, 0, 12}] (* Jean-François Alcover, Feb 25 2015, after Alois P. Heinz *)
-
a(n) = A(n+1,n) \\ A defined in A028657. - Andrew Howroyd, Mar 01 2023
A006383
Number of equivalence classes of n X n binary matrices when one can permute rows, permute columns and complement columns.
Original entry on oeis.org
1, 1, 3, 7, 41, 299, 6128, 343656, 67013431, 45770163273, 108577103160005, 886929528971819040, 24943191706060101926577, 2425246700258693990625775794, 820270898724825121532156178527106
Offset: 0
a(2) = 3:
00 10 11
00 00 00
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
- Andrew Howroyd, Table of n, a(n) for n = 0..50 (terms 0..35 from Sean A. Irvine)
- M. A. Harrison, On the number of classes of binary matrices, IEEE Trans. Computers, 22 (1973), 1048-1051.
- M. A. Harrison, On the number of classes of binary matrices, IEEE Transactions on Computers, C-22.12 (1973), 1048-1052. (Annotated scanned copy)
- Index entries for sequences related to binary matrices
A052269
Number of n X n matrices over GF(3) up to row and column permutations.
Original entry on oeis.org
1, 3, 27, 738, 90492, 64796982, 302752867740, 9610448114487414, 2130536585704570302966, 3379836486315342147630795474, 39197947672609240635681299333726499, 3385559039111928075792568062997302563515455, 2212558055097091715366351569353345370930731329332056
Offset: 0
A052366
Number of nonnegative integer 4 X 4 matrices with sum of elements equal to n, under row and column permutations.
Original entry on oeis.org
1, 1, 4, 10, 33, 78, 224, 549, 1403, 3292, 7677, 16934, 36581, 75732, 152949, 298784, 569636, 1056500, 1916502, 3396630, 5901524, 10051384, 16820192, 27664756, 44795247, 71442327, 112366941, 174384376, 267289440, 404838044, 606375995
Offset: 0
A052371
Triangle T(n,k) of n X n binary matrices with k=0...n^2 ones up to row and column permutations.
Original entry on oeis.org
1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 3, 6, 7, 7, 6, 3, 1, 1, 1, 1, 3, 6, 16, 21, 39, 44, 55, 44, 39, 21, 16, 6, 3, 1, 1, 1, 1, 3, 6, 16, 34, 69, 130, 234, 367, 527, 669, 755, 755, 669, 527, 367, 234, 130, 69, 34, 16, 6, 3, 1, 1
Offset: 0
Triangle begins:
1;
1, 1;
1, 1, 3, 1, 1;
1, 1, 3, 6, 7, 7, 6, 3, 1, 1;
1, 1, 3, 6, 16, 21, 39, 44, 55, 44, 39, 21, 16, 6, 3, 1, 1;
...
(the last block giving the numbers of 4 X 4 binary matrices with k=0..16 ones up to row and column permutations).
-
permcount[v_] := Module[{m = 1, s = 0, t, i, k = 0}, 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_, q_] := Product[(1 + x^LCM[p[[i]], q[[j]]])^GCD[p[[i]], q[[j]]], {i, 1, Length[p]}, {j, 1, Length[q]}];
row[n_] := Module[{s = 0}, Do[Do[s += permcount[p]*permcount[q]*c[p, q], {q, IntegerPartitions[n]}], {p, IntegerPartitions[n]}]; CoefficientList[ s/(n!^2), x]]
row /@ Range[0, 5] // Flatten (* Jean-François Alcover, Sep 22 2019, after Andrew Howroyd *)
-
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)={prod(i=1, #p, prod(j=1, #q, (1 + x^lcm(p[i], q[j]))^gcd(p[i], q[j])))}
row(n)={my(s=0); forpart(p=n, forpart(q=n, s+=permcount(p) * permcount(q) * c(p, q))); Vec(s/(n!^2))}
for(n=1, 5, print(row(n))) \\ Andrew Howroyd, Nov 14 2018
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
- Alois P. Heinz, Table of n, a(n) for n = 1..1000
- Marko R. Riedel, Number of equivalence classes of matrices, Math Stackexchange.
- Marko R. Riedel, Computing the cycle index for arbitary k x l matrices using Maple
- Index entries for linear recurrences with constant coefficients, signature (10,-45,120,-210,252,-210,120,-45,10,-1).
-
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 *)
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
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