A316983
Number of non-isomorphic self-dual multiset partitions of weight n.
Original entry on oeis.org
1, 1, 2, 4, 9, 17, 36, 72, 155, 319, 677, 1429, 3094, 6648, 14518, 31796, 70491, 156818, 352371, 795952, 1813580, 4155367, 9594425, 22283566, 52122379, 122631874, 290432439, 691831161, 1658270316, 3997272089, 9692519896, 23631827354, 57943821449, 142834652193
Offset: 0
Non-isomorphic representatives of the a(4) = 9 self-dual multiset partitions:
(1111),
(1)(222), (2)(122), (11)(22), (12)(12),
(1)(1)(23), (1)(2)(33), (1)(3)(23),
(1)(2)(3)(4).
The a(4) = 9 square symmetric matrices:
. [4]
.
. [3 0] [2 0] [2 1] [1 1]
. [0 1] [0 2] [1 0] [1 1]
.
. [2 0 0] [1 1 0] [0 1 1]
. [0 1 0] [1 0 0] [1 0 0]
. [0 0 1] [0 0 1] [1 0 0]
.
. [1 0 0 0]
. [0 1 0 0]
. [0 0 1 0]
. [0 0 0 1]
A138178
Number of symmetric matrices with nonnegative integer entries and without zero rows or columns such that sum of all entries is equal to n.
Original entry on oeis.org
1, 1, 3, 9, 33, 125, 531, 2349, 11205, 55589, 291423, 1583485, 8985813, 52661609, 319898103, 2000390153, 12898434825, 85374842121, 580479540219, 4041838056561, 28824970996809, 210092964771637, 1564766851282299, 11890096357039749, 92151199272181629
Offset: 0
a(4) = 33 because there are 1 such matrix of type 1 X 1, 7 matrices of type 2 X 2, 15 of type 3 X 3 and 10 of type 4 X 4, cf. A138177.
From _Gus Wiseman_, Feb 23 2018: (Start)
The a(3) = 9 normal semistandard Young tableaux:
1 1 2 1 3 1 2 1 1 1 2 3 1 2 2 1 1 2 1 1 1
2 3 2 2 2
3
(End)
From _Gus Wiseman_, Nov 14 2018: (Start)
The a(4) = 33 matrices:
[4]
.
[30][21][20][11][10][02][01]
[01][10][02][11][03][20][12]
.
[200][200][110][101][100][100][100][100][011][010][010][010][001][001][001]
[010][001][100][010][020][011][010][001][100][110][101][100][020][010][001]
[001][010][001][100][001][010][002][011][100][001][010][002][100][101][110]
.
[1000][1000][1000][1000][0100][0100][0010][0010][0001][0001]
[0100][0100][0010][0001][1000][1000][0100][0001][0100][0010]
[0010][0001][0100][0010][0010][0001][1000][1000][0010][0100]
[0001][0010][0001][0100][0001][0010][0001][0100][1000][1000]
(End)
-
gf:= proc(j) local k, n; add(add((-1)^(n-k) *binomial(n, k) *(1-x)^(-k) *(1-x^2)^(-binomial(k, 2)), k=0..n), n=0..j) end: a:= n-> coeftayl(gf(n+1), x=0, n): seq(a(n), n=0..25); # Alois P. Heinz, Sep 25 2008
-
Table[Sum[SeriesCoefficient[1/(2^(k+1)*(1-x)^k*(1-x^2)^(k*(k-1)/2)),{x,0,n}],{k,0,Infinity}],{n,0,20}] (* Vaclav Kotesovec, Jul 03 2014 *)
multsubs[set_,k_]:=If[k==0,{{}},Join@@Table[Prepend[#,set[[i]]]&/@multsubs[Drop[set,i-1],k-1],{i,Length[set]}]]; Table[Length[Select[multsubs[Tuples[Range[n],2],n],And[Union[First/@#]==Range[Max@@First/@#],Union[Last/@#]==Range[Max@@Last/@#],Sort[Reverse/@#]==#]&]],{n,5}] (* Gus Wiseman, Nov 14 2018 *)
A321405
Number of non-isomorphic self-dual set systems of weight n.
Original entry on oeis.org
1, 1, 1, 2, 2, 3, 6, 9, 16, 28, 47
Offset: 0
Non-isomorphic representatives of the a(1) = 1 through a(8) = 16 set systems:
{{1}} {{1}{2}} {{2}{12}} {{1}{3}{23}} {{2}{13}{23}}
{{1}{2}{3}} {{1}{2}{3}{4}} {{1}{2}{4}{34}}
{{1}{2}{3}{4}{5}}
.
{{12}{13}{23}} {{13}{23}{123}} {{1}{13}{14}{234}}
{{3}{23}{123}} {{1}{23}{24}{34}} {{12}{13}{24}{34}}
{{1}{3}{24}{34}} {{1}{4}{34}{234}} {{1}{24}{34}{234}}
{{2}{4}{12}{34}} {{2}{13}{24}{34}} {{2}{14}{34}{234}}
{{1}{2}{3}{5}{45}} {{3}{4}{14}{234}} {{3}{4}{134}{234}}
{{1}{2}{3}{4}{5}{6}} {{1}{2}{4}{35}{45}} {{4}{13}{14}{234}}
{{1}{3}{5}{23}{45}} {{1}{2}{34}{35}{45}}
{{1}{2}{3}{4}{6}{56}} {{1}{2}{5}{45}{345}}
{{1}{2}{3}{4}{5}{6}{7}} {{1}{3}{24}{35}{45}}
{{1}{4}{5}{25}{345}}
{{2}{4}{12}{35}{45}}
{{4}{5}{13}{23}{45}}
{{1}{2}{3}{5}{46}{56}}
{{1}{2}{4}{6}{34}{56}}
{{1}{2}{3}{4}{5}{7}{67}}
{{1}{2}{3}{4}{5}{6}{7}{8}}
A055884
Euler transform of partition triangle A008284.
Original entry on oeis.org
1, 1, 2, 1, 2, 3, 1, 4, 4, 5, 1, 4, 8, 7, 7, 1, 6, 12, 16, 12, 11, 1, 6, 17, 25, 28, 19, 15, 1, 8, 22, 43, 49, 48, 30, 22, 1, 8, 30, 58, 87, 88, 77, 45, 30, 1, 10, 36, 87, 134, 167, 151, 122, 67, 42, 1, 10, 45, 113, 207, 270, 296, 247, 185, 97, 56, 1, 12, 54, 155, 295, 448, 510, 507, 394, 278, 139, 77
Offset: 1
From _Gus Wiseman_, Nov 09 2018: (Start)
Triangle begins:
1
1 2
1 2 3
1 4 4 5
1 4 8 7 7
1 6 12 16 12 11
1 6 17 25 28 19 15
1 8 22 43 49 48 30 22
1 8 30 58 87 88 77 45 30
...
The fifth row {1, 4, 8, 7, 7} counts the following multiset partitions:
{{5}} {{1,4}} {{1,1,3}} {{1,1,1,2}} {{1,1,1,1,1}}
{{2,3}} {{1,2,2}} {{1},{1,1,2}} {{1},{1,1,1,1}}
{{1},{4}} {{1},{1,3}} {{1,1},{1,2}} {{1,1},{1,1,1}}
{{2},{3}} {{1},{2,2}} {{2},{1,1,1}} {{1},{1},{1,1,1}}
{{2},{1,2}} {{1},{1},{1,2}} {{1},{1,1},{1,1}}
{{3},{1,1}} {{1},{2},{1,1}} {{1},{1},{1},{1,1}}
{{1},{1},{3}} {{1},{1},{1},{2}} {{1},{1},{1},{1},{1}}
{{1},{2},{2}}
(End)
-
h:= proc(n, i) option remember; expand(`if`(n=0, 1,
`if`(i<1, 0, h(n, i-1)+x*h(n-i, min(n-i, i)))))
end:
g:= proc(n, i, j) option remember; expand(`if`(j=0, 1, `if`(i<0, 0, add(
g(n, i-1, j-k)*x^(i*k)*binomial(coeff(h(n$2), x, i)+k-1, k), k=0..j))))
end:
b:= proc(n, i) option remember; expand(`if`(n=0, 1,
`if`(i<1, 0, add(b(n-i*j, i-1)*g(i$2, j), j=0..n/i))))
end:
T:= (n, k)-> coeff(b(n$2), x, k):
seq(seq(T(n,k), k=1..n), n=1..12); # Alois P. Heinz, Feb 17 2023
-
sps[{}]:={{}};sps[set:{i_,_}]:=Join@@Function[s,Prepend[#,s]&/@sps[Complement[set,s]]]/@Cases[Subsets[set],{i,_}];
mps[set_]:=Union[Sort[Sort/@(#/.x_Integer:>set[[x]])]&/@sps[Range[Length[set]]]];
Table[Length[Join@@mps/@IntegerPartitions[n,{k}]],{n,5},{k,n}] (* Gus Wiseman, Nov 09 2018 *)
A320797
Number of non-isomorphic self-dual multiset partitions of weight n with no singletons.
Original entry on oeis.org
1, 0, 1, 1, 3, 4, 9, 15, 33, 60, 121
Offset: 0
Non-isomorphic representatives of the a(2) = 1 through a(7) = 15 multiset partitions:
{{11}} {{111}} {{1111}} {{11111}} {{111111}} {{1111111}}
{{11}{22}} {{11}{122}} {{111}{222}} {{111}{1222}}
{{12}{12}} {{11}{222}} {{112}{122}} {{111}{2222}}
{{12}{122}} {{11}{2222}} {{112}{1222}}
{{12}{1222}} {{11}{22222}}
{{22}{1122}} {{12}{12222}}
{{11}{22}{33}} {{122}{1122}}
{{11}{23}{23}} {{22}{11222}}
{{12}{13}{23}} {{11}{12}{233}}
{{11}{22}{233}}
{{11}{22}{333}}
{{11}{23}{233}}
{{12}{12}{333}}
{{12}{13}{233}}
{{13}{23}{123}}
Inequivalent representatives of the a(6) = 9 symmetric matrices with no rows or columns summing to 1:
[6]
.
[3 0] [2 1] [4 0] [3 1] [2 2]
[0 3] [1 2] [0 2] [1 1] [2 0]
.
[2 0 0] [2 0 0] [1 1 0]
[0 2 0] [0 1 1] [1 0 1]
[0 0 2] [0 1 1] [0 1 1]
A320808
Regular tetrangle where T(n,k,i) is the number of nonnegative integer matrices up to row and column permutations with no zero rows or columns and k nonzero entries summing to n, with i columns.
Original entry on oeis.org
1, 0, 0, 1, 0, 0, 1, 0, 1, 2, 0, 0, 1, 0, 1, 2, 0, 1, 2, 3, 0, 0, 1, 0, 2, 4, 0, 1, 5, 4, 0, 1, 5, 5, 5, 0, 0, 1, 0, 2, 4, 0, 2, 10, 8, 0, 1, 9, 13, 7, 0, 1, 5, 12, 9, 7, 0, 0, 1, 0, 3, 6, 0, 3, 16, 12, 0, 2, 24, 33, 16, 0, 1, 14, 36, 29, 12, 0, 1, 9, 23, 29
Offset: 1
Tetrangle begins:
1 0 0 0 0 0
0 1 0 1 0 1 0 1 0 1
0 1 2 0 1 2 0 2 4 0 2 4
0 1 2 3 0 1 5 4 0 2 10 8
0 1 5 5 5 0 1 9 13 7
0 1 5 12 9 7
Triangle sums are
A007716. Triangle of row sums is
A320801. Triangle of column sums is
A317533. Triangle of last columns (without its leading column 1,0,0,0,...) is
A055884.
A135588
Number of symmetric (0,1)-matrices with exactly n entries equal to 1 and no zero rows or columns.
Original entry on oeis.org
1, 1, 2, 6, 20, 74, 302, 1314, 6122, 29982, 154718, 831986, 4667070, 27118610, 163264862, 1013640242, 6488705638, 42687497378, 288492113950, 1998190669298, 14177192483742, 102856494496050, 762657487965086, 5771613810502002, 44555989658479726, 350503696871063138
Offset: 0
From _Gus Wiseman_, Nov 14 2018: (Start)
The a(4) = 20 matrices:
[11]
[11]
.
[110][101][100][100][011][010][010][001][001]
[100][010][011][001][100][110][101][010][001]
[001][100][010][011][100][001][010][101][110]
.
[1000][1000][1000][1000][0100][0100][0010][0010][0001][0001]
[0100][0100][0010][0001][1000][1000][0100][0001][0100][0010]
[0010][0001][0100][0010][0010][0001][1000][1000][0010][0100]
[0001][0010][0001][0100][0001][0010][0001][0100][1000][1000]
(End)
Cf.
A049311,
A054976,
A101370,
A104601,
A104602,
A120733,
A138178,
A283877,
A316983,
A320796,
A321401,
A321405.
-
Table[Sum[SeriesCoefficient[(1+x)^k*(1+x^2)^(k*(k-1)/2)/2^(k+1),{x,0,n}],{k,0,Infinity}],{n,0,20}] (* Vaclav Kotesovec, Jul 02 2014 *)
Join[{1}, Table[Length[Select[Subsets[Tuples[Range[n], 2], {n}], And[Union[First/@#]==Range[Max@@First/@#], Union[Last/@#]==Range[Max@@Last/@#], Sort[Reverse/@#]==#]&]], {n, 5}]] (* Gus Wiseman, Nov 14 2018 *)
A320801
Regular triangle read by rows where T(n,k) is the number of nonnegative integer matrices up to row and column permutations with no zero rows or columns and k nonzero entries summing to n.
Original entry on oeis.org
1, 0, 1, 0, 1, 3, 0, 1, 3, 6, 0, 1, 6, 10, 16, 0, 1, 6, 20, 30, 34, 0, 1, 9, 31, 75, 92, 90, 0, 1, 9, 45, 126, 246, 272, 211, 0, 1, 12, 60, 223, 501, 839, 823, 558, 0, 1, 12, 81, 324, 953, 1900, 2762, 2482, 1430, 0, 1, 15, 100, 491, 1611, 4033, 7120, 9299, 7629, 3908
Offset: 0
Triangle begins:
1
0 1
0 1 3
0 1 3 6
0 1 6 10 16
0 1 6 20 30 34
0 1 9 31 75 92 90
0 1 9 45 126 246 272 211
0 1 12 60 223 501 839 823 558
-
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}
K(q, t, k)={prod(j=1, #q, my(g=gcd(t, q[j]), e=(q[j]/g)); (1 - y^e + y^e/(1 - x^e) + O(x*x^k))^g) - 1}
G(n)={my(s=0); forpart(q=n, s+=permcount(q)*exp(sum(t=1, n, substvec(K(q, t, n\t)/t, [x,y], [x^t,y^t])) + O(x*x^n))); s/n!}
T(n)=[Vecrev(p) | p<-Vec(G(n))]
{ my(A=T(10)); for(i=1, #A, print(A[i])) } \\ Andrew Howroyd, Jan 16 2024
A321401
Number of non-isomorphic strict self-dual multiset partitions of weight n.
Original entry on oeis.org
1, 1, 2, 4, 7, 14, 29, 57, 117, 240, 498
Offset: 0
Non-isomorphic representatives of the a(1) = 1 through a(5) = 14 multiset partitions:
{{1}} {{1,1}} {{1,1,1}} {{1,1,1,1}} {{1,1,1,1,1}}
{{1},{2}} {{1},{2,2}} {{1,1},{2,2}} {{1,1},{1,2,2}}
{{2},{1,2}} {{1},{2,2,2}} {{1,1},{2,2,2}}
{{1},{2},{3}} {{2},{1,2,2}} {{1,2},{1,2,2}}
{{1},{2},{3,3}} {{1},{2,2,2,2}}
{{1},{3},{2,3}} {{2},{1,2,2,2}}
{{1},{2},{3},{4}} {{1},{2,2},{3,3}}
{{1},{2},{3,3,3}}
{{1},{3},{2,3,3}}
{{2},{1,2},{3,3}}
{{2},{1,3},{2,3}}
{{1},{2},{3},{4,4}}
{{1},{2},{4},{3,4}}
{{1},{2},{3},{4},{5}}
A321406
Number of non-isomorphic self-dual set systems of weight n with no singletons.
Original entry on oeis.org
1, 0, 0, 0, 0, 0, 1, 1, 1, 2, 4
Offset: 0
Non-isomorphic representatives of the a(6) = 1 through a(10) = 4 set systems:
6: {{1,2},{1,3},{2,3}}
7: {{1,3},{2,3},{1,2,3}}
8: {{1,2},{1,3},{2,4},{3,4}}
9: {{1,2},{1,3},{1,4},{2,3,4}}
9: {{1,2},{1,4},{3,4},{2,3,4}}
10: {{1,2},{2,4},{1,3,4},{2,3,4}}
10: {{1,3},{2,4},{1,3,4},{2,3,4}}
10: {{1,4},{2,4},{3,4},{1,2,3,4}}
10: {{1,2},{1,3},{2,4},{3,5},{4,5}}
Showing 1-10 of 18 results.
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