A053307 -id:A053307 - cp's OEIS frontend

A007716 Number of polynomial symmetric functions of matrix of order n under separate row and column permutations.

1, 1, 4, 10, 33, 91, 298, 910, 3017, 9945, 34207, 119369, 429250, 1574224, 5916148, 22699830, 89003059, 356058540, 1453080087, 6044132794, 25612598436, 110503627621, 485161348047, 2166488899642, 9835209912767, 45370059225318, 212582817739535, 1011306624512711

Offset: 0

Colin Mallows

Also, the number of nonnegative integer n X n matrices with sum of elements equal to n, under row and column permutations (cf. A120733).
This is a two-dimensional generalization of the partition function (A000041), which equals the number of length n vectors of nonnegative integers with sum n, equivalent under permutations. - Franklin T. Adams-Watters, Sep 19 2011
Also number of non-isomorphic multiset partitions of weight n. - Gus Wiseman, Sep 19 2011

			The 10 non-isomorphic multiset partitions of weight 3 are {{1, 1, 1}}, {{1, 1, 2}}, {{1, 2, 3}}, {{1}, {1, 1}}, {{1}, {1, 2}}, {{1}, {2, 2}}, {{1}, {2, 3}}, {{1}, {1}, {1}}, {{1}, {1}, {2}}, {{1}, {2}, {3}}.

Andrew Howroyd, Table of n, a(n) for n = 0..50 (terms 0..30 from Seiichi Manyama)

Main diagonal of A318795.

Cf. A053307, A052365, A052366, A052367, A052372, A052373, A049311, A054688, A000041.

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];
c[p_, q_, 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_] := a[n] = M[n, n, n];
Table[Print[n, " ", a[n]]; a[n], {n, 0, 18}] (* Jean-François Alcover, May 03 2019, after Andrew Howroyd *)

\\ See A318795
a(n) = M(n,n,n); \\ Andrew Howroyd, Sep 03 2018

EulerT(v)={Vec(exp(x*Ser(dirmul(v,vector(#v,n,1/n))))-1, -#v)}
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)={EulerT(Vec(sum(j=1, #q, gcd(t, q[j])*x^lcm(t,q[j])) + O(x*x^k), -k))}
a(n)={my(s=0); forpart(q=n, s+=permcount(q)*polcoef(exp(x*Ser(sum(t=1, n, K(q,t,n)/t))), n)); s/n!} \\ Andrew Howroyd, Mar 29 2020

a(n) is the coefficient of x^n in the cycle index Z(S_n X S_n; x_1, x_2, ...) if we replace x_i with 1+x^i+x^(2*i)+x^(3*i)+x^(4*i)+..., where S_n X S_n is the Cartesian product of symmetric groups S_n of degree n. - Vladeta Jovovic, Mar 09 2000

More terms from Vladeta Jovovic, Jun 28 2000
a(19)-a(25) from Max Alekseyev, Jan 22 2010
a(0)=1 prepended by Alois P. Heinz, Feb 03 2019
a(26)-a(27) from Seiichi Manyama, Nov 23 2019

A008795 Molien series for 3-dimensional representation of dihedral group D_6 of order 6.

Original entry on oeis.org

1, 0, 3, 1, 6, 3, 10, 6, 15, 10, 21, 15, 28, 21, 36, 28, 45, 36, 55, 45, 66, 55, 78, 66, 91, 78, 105, 91, 120, 105, 136, 120, 153, 136, 171, 153, 190, 171, 210, 190, 231, 210, 253, 231, 276, 253, 300, 276, 325, 300, 351, 325, 378, 351, 406, 378, 435, 406, 465, 435, 496, 465, 528, 496

Offset: 0

N. J. A. Sloane

a(n-3) is the number of ordered triples of positive integers which are the side lengths of a nondegenerate triangle of perimeter n. - Rob Pratt, Jul 12 2004
a(n) is the number of ways to distribute n identical objects into 3 distinguishable bins so that no bin contains an absolute majority of objects. - Geoffrey Critzer, Mar 17 2010
From Omar E. Pol, Feb 05 2012: (Start)
Also terms of A000217 and A000217-shifted interleaved.
Also 0 together with this sequence give the first row of the square array A194801. (End)
a(n) is the number of coins left after packing 3-curves coins patterns into fountain of coins base n. Refer to A005169: "A fountain is formed by starting with a row of coins, then stacking additional coins on top so that each new coin touches two in the previous row". See illustration in links. - Kival Ngaokrajang, Oct 12 2013

Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Kival Ngaokrajang, Illustration of initial terms
Ira Rosenholtz, Problem 1584, Mathematics Magazine, Vol. 72 (1999), p. 408.
Index entries for sequences related to groups
Index entries for Molien series
Index entries for linear recurrences with constant coefficients, signature (1,2,-2,-1,1).

Cf. A005044.

First differences of A053307.

a := [1,0,3,1,6];; for n in [6..70] do a[n] := a[n-1] + 2*a[n-2] -2*a[n-3] -a[n-4] +a[n-5]; od; a; # Muniru A Asiru, Feb 01 2018

[(2*n^2+6*n+7)/16+3*(2*n+3)*(-1)^n/16: n in [0..70] ]; // Vincenzo Librandi, Aug 21 2011

a:= n-> binomial(n/2+2-3*irem(n, 2)/2, 2):
seq(a(n), n=0..70); # Muniru A Asiru, Feb 01 2018

Table[If[EvenQ[n], Binomial[n/2+2, 2], Binomial[(n+1)/2, 2]], {n, 0, 70}]
CoefficientList[Series[(1+x^3)/(1-x^2)^3, {x, 0, 70}], x] (* Robert G. Wilson v, Feb 05 2012 *)
a[ n_]:= Binomial[ Quotient[n, 2] + 2 - Mod[n, 2], 2]; (* Michael Somos, Feb 01 2018 *)
a[ n_]:= With[ {m = If[ n < 0, -3 - n, n]}, SeriesCoefficient[ (1 - x + x^2) / ((1 - x)^3 (1 + x)^2), {x, 0, m}]]; (* Michael Somos, Feb 01 2018 *)
LinearRecurrence[{1,2,-2,-1,1}, {1,0,3,1,6}, 70] (* Robert G. Wilson v, Feb 01 2018 *)

a(n)=(2*n^2+6*n+7)/16+3*(2*n+3)*(-1)^n/16 \\ Charles R Greathouse IV, Oct 22 2015

{a(n) = binomial(n\2 + 2 - n%2, 2)}; /* Michael Somos, Feb 01 2018 */

[(2*n^2 +6*n +7 +3*(2*n+3)*(-1)^n)/16 for n in (0..70)] # G. C. Greubel, Sep 11 2019

The signed version with g.f. (1-x^3)/(1-x^2)^3 is the inverse binomial transform of A084861. - Paul Barry, Jun 12 2003
a(n) = binomial(n/2+2, 2) for n even, binomial((n+1)/2, 2) for n odd. - Rob Pratt, Jul 12 2004
From Paul Barry, Jul 29 2004: (Start)
a(n-2) interleaves n(n+1)/2 and n(n-1)/2.
G.f.: (1-x+x^2)/((1+x)^2*(1-x)^3).
a(n) = (2*n^2 + 6*n + 7 + 3*(2*n+3)*(-1)^n)/16. (End)
a(n) = n*(n+1)/2, n = +- 1, +- 2... - Omar E. Pol, Feb 05 2012
From Michael Somos, Feb 01 2018: (Start)
Euler transform of length 6 sequence [0, 3, 1, 0, 0, -1].
G.f.: (1 + x^3) / (1 - x^2)^3.
a(n) = a(-3-n) for all in Z. (End)

Definition clarified by N. J. A. Sloane, Feb 02 2018

A100157 Structured rhombic dodecahedral numbers (vertex structure 9).

Original entry on oeis.org

1, 14, 55, 140, 285, 506, 819, 1240, 1785, 2470, 3311, 4324, 5525, 6930, 8555, 10416, 12529, 14910, 17575, 20540, 23821, 27434, 31395, 35720, 40425, 45526, 51039, 56980, 63365, 70210, 77531, 85344, 93665, 102510, 111895, 121836, 132349, 143450, 155155, 167480

Offset: 1

James A. Record (james.record(AT)gmail.com), Nov 07 2004

Also structured triakis octahedral numbers (vertex structure 9) (Cf. A100171 = alternate vertex); and structured heptagonal anti-prism numbers (Cf. A100185 = structured anti-prisms).
If Y is a 2-subset of a 2n-set X then, for n>=2, a(n-1) is the number of 4-subsets of X intersecting Y. - Milan Janjic, Nov 18 2007
Let M(2n-1) be a (2n-1)x(2n-1) matrix whose (i,j)-entry equals i^2/(i^2+sqrt(-1)) if i=j and equals 1 otherwise. Then a(n) equals (-1)^(n+1) times the real part of prod(k^2+sqrt(-1),k=1...2n-1) times the determinant of M(2n-1). - John M. Campbell, Sep 07 2011
Principal diagonal of the convolution array A213752. - Clark Kimberling, Jun 20 2012
The Fuss-Catalan numbers are Cat(d,k)= [1/(k*(d-1)+1)]*binomial(k*d,k) and enumerate the number of (d+1)-gon partitions of a (k*(d-1)+2)-gon (cf. Whieldon and Schuetz link). a(n)= Cat(n,4), so enumerates the number of (n+1)-gon partitions of a (4*(n-1)+2)-gon. Analogous series are A000326 (k=3) and A234043 (k=5). Also, a(n)= A006918(4n+1) = A008610(4n+1) = A053307(4n+1) with offset=0. - Tom Copeland, Oct 05 2014

			For n=4, sum( (4+i)^2, i=-3..3 ) = (4-3)^2+(4-2)^2+(4-1)^2+(4-0)^2+(4+1)^2+(4+2)^2+(4+3)^2 = 140 = a(4). - _Bruno Berselli_, Jul 24 2014

Jolley, Summation of Series, Dover (1961).

Vincenzo Librandi, Table of n, a(n) for n = 1..5000
Milan Janjic, Two Enumerative Functions.
A. Schuetz and G. Whieldon, Polygonal Dissections and Reversions of Series, arXiv:1401.7194 [math.CO], 2014.
StackExchange, What is a Structured Polyhedron?
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Cf. A005915 = alternate vertex; A100145 for more on structured polyhedral numbers.

Cf. A000330, A000326, A006918, A008610, A053307, A100171, A100185, A213752, A234043.

[(1/6)*(16*n^3-12*n^2+2*n): n in [1..40]]; // Vincenzo Librandi, Jul 19 2011

with(combstruct):ZL:=[st, {st=Prod(left, right), left=Set(U, card=r), right=Set(U, card=r), U=Sequence(Z, card>=1)}, unlabeled]: subs(r=1, stack): seq(count(subs(r=2, ZL), size=m*4), m=1..32) ; # Zerinvary Lajos, Jan 02 2008

a(n)=(16*n^3-12*n^2+2*n)/6 \\ Charles R Greathouse IV, Sep 24 2015

a(n) = (16*n^3 - 12*n^2 + 2*n)/6.
a(n) = n*(2*n-1)*(4*n-1)/3 = A000330(2*n-1). - Reinhard Zumkeller, Jul 06 2009
Sum_{n>=1} 1/(24*a(n)) = Pi/8-log(2)/2 = 0.046125491418751... [Jolley eq. 251]
G.f.: x*(1+10*x+5*x^2)/(x-1)^4. - R. J. Mathar, Oct 03 2011
a(n) = binomial(2*n+1,3) + binomial(2*n,3). - John Molokach, Jul 10 2013
a(n) = Sum_{i=-(n-1)..(n-1)} (n+i)^2. - Bruno Berselli, Jul 24 2014
From Elmo R. Oliveira, Aug 04 2025: (Start)
E.g.f.: exp(x)*x*(8*x^2 + 18*x + 3)/3.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 4. (End)

A008804 Expansion of 1/((1-x)^2(1-x^2)(1-x^4)).

Original entry on oeis.org

1, 2, 4, 6, 10, 14, 20, 26, 35, 44, 56, 68, 84, 100, 120, 140, 165, 190, 220, 250, 286, 322, 364, 406, 455, 504, 560, 616, 680, 744, 816, 888, 969, 1050, 1140, 1230, 1330, 1430, 1540, 1650, 1771, 1892, 2024, 2156, 2300, 2444, 2600, 2756, 2925, 3094, 3276, 3458

Offset: 0

N. J. A. Sloane

b(n)=a(n-3) is the number of asymmetric nonnegative integer 2 X 2 matrices with sum of elements equal to n, under action of dihedral group D_4(b(0)=b(1)=b(2)=0). G.f. for b(n) is x^3/((1-x)^2*(1-x^2)*(1-x^4)). - Vladeta Jovovic, May 07 2000
If the offset is changed to 5, this is the 2nd Witt transform of A004526 [Moree]. - R. J. Mathar, Nov 08 2008
a(n) is the number of partitions of 2*n into powers of 2 less than or equal to 2^3. First differs from A000123 at n=8. - Alois P. Heinz, Apr 02 2012
a(n) is the number of bracelets with 4 black beads and n+3 white beads which have no reflection symmetry. For n=1 we have for example 2 such bracelets with 4 black beads and 4 white beads: BBBWBWWW and BBWBWBWW. - Herbert Kociemba, Nov 27 2016
a(n) is the also number of aperiodic bracelets with 4 black beads and n+3 white beads which have no reflection symmetry. This is equivalent to saying that a(n) is the (n+7)th element of the DHK[4] (bracelet, identity, unlabeled, 4 parts) transform of 1, 1, 1, ... (see Bower's link about transforms). Thus, for n >= 1 , a(n) = (DHK[4] c){n+7}, where c = (1 : n >= 1). This is because every bracelet with 4 black beads and n+3 white beads which has no reflection symmetry must also be aperiodic. This statement is not true anymore if we have k black beads where k is even >= 6. - _Petros Hadjicostas, Feb 24 2019

			G.f. = 1 + 2*x + 4*x^2 + 6*x^3 + 10*x^4 + 14*x^5 + 20*x^6 + 26*x^7 + 35*x^8 + ...
There are 10 asymmetric nonnegative integer 2 X 2 matrices with sum of elements equal to 7 under action of D_4:
[0 0] [0 0] [0 0] [0 1] [0 1] [0 1] [0 1] [0 2] [0 2] [1 1]
[1 6] [2 5] [3 4] [2 4] [3 3] [4 2] [5 1] [3 2] [4 1] [2 3]

T. D. Noe, Table of n, a(n) for n = 0..1000
C. G. Bower, Transforms (2)
Petros Hadjicostas, The aperiodic version of Herbert Kociemba's formula for bracelets with no reflection symmetry, 2019.
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 197
Pieter Moree, The formal series Witt transform, Discr. Math. no. 295 vol. 1-3 (2005) 143-160. [From _R. J. Mathar_, Nov 08 2008]
Index entries for linear recurrences with constant coefficients, signature (2,0,-2,2,-2,0,2,-1).

Cf. A000123, A001400, A002620, A004526, A005232, A014557, A032246, A032248, A053307.

Column k=3 of A181322. Column k = 4 of A180472 (but with different offset).

a:=[1,2,4,6,10,14,20,26];; for n in [9..60] do a[n]:=2*a[n-1] -2*a[n-3]+2*a[n-4]-2*a[n-5]+2*a[n-7]-a[n-8]; od; a; # G. C. Greubel, Sep 12 2019

R:=PowerSeriesRing(Integers(), 60); Coefficients(R!( 1/((1-x)^2*(1-x^2)*(1-x^4)) )); // G. C. Greubel, Sep 12 2019

seq(coeff(series(1/((1-x)^2*(1-x^2)*(1-x^4)), x, n+1), x, n), n = 0..60); # G. C. Greubel, Sep 12 2019

LinearRecurrence[{2,0,-2,2,-2,0,2,-1}, {1,2,4,6,10,14,20,26}, 60] (* Vladimir Joseph Stephan Orlovsky, Feb 23 2012 *)
gf[x_,k_]:=x^k/2 (1/k Plus@@(EulerPhi[#] (1-x^#)^(-(k/#))&/@Divisors[k])-(1+x)/(1-x^2)^Floor[k/2+1]); CoefficientList[Series[gf[x,4]/x^7,{x,0,60}],x] (* Herbert Kociemba, Nov 27 2016 *)
Table[(84 +12*(-1)^n +85*n +3*(-1)^n*n +24*n^2 +2*n^3 +12*Sin[n Pi/2])/96, {n,0,60}] (* Eric W. Weisstein, Oct 12 2017 *)
CoefficientList[Series[1/((1-x)^4*(1+x)^2*(1+x^2)), {x,0,60}], x] (* Eric W. Weisstein, Oct 12 2017 *)

a(n)=(84+12*(-1)^n+6*I*((-I)^n-I^n)+(85+3*(-1)^n)*n+24*n^2 +2*n^3)/96 \\ Jaume Oliver Lafont, Sep 20 2009

{a(n) = my(s = 1); if( n<-7, n = -8 - n; s = -1); if( n<0, 0, s * polcoeff( 1 / ((1 - x)^2 * (1 - x^2) * (1 - x^4)) + x * O(x^n), n))}; /* Michael Somos, Feb 02 2011 */

def A008804_list(prec):
    P. = PowerSeriesRing(ZZ, prec)
    return P(1/((1-x)^2*(1-x^2)*(1-x^4))).list()
A008804_list(60) # G. C. Greubel, Sep 12 2019

For a formula for a(n) see A014557.
a(n) = (84 +85*n +24*n^2 +2*n^3 +12*A056594(n+3) +3*(-1)^n*(n+4))/96. - R. J. Mathar, Nov 08 2008
a(n) = 2*(Sum_{k=0..floor(n/2)} A002620(k+2)) - A002620(n/2+2)*(1+(-1)^n)/2. - Paul Barry, Mar 05 2009
G.f.: 1/((1-x)^4*(1+x)^2*(1+x^2)). - Jaume Oliver Lafont, Sep 20 2009
Euler transform of length 4 sequence [2, 1, 0, 1]. - Michael Somos, Feb 05 2011
a(n) = -a(-8 - n) for all n in Z. - Michael Somos, Feb 05 2011
From Herbert Kociemba, Nov 27 2016: (Start)
More generally gf(k) is the g.f. for the number of bracelets without reflection symmetry with k black beads and n-k white beads.
gf(k): x^k/2 * ( (1/k)*Sum_{n|k} phi(n)/(1 - x^n)^(k/n) - (1 + x)/(1 -x^2)^floor(k/2 + 1) ). The g.f. here is gf(4)/x^7 because of the different offset. (End)
E.g.f.: ((48 + 54*x + 15*x^2 + x^3)*cosh(x) + 6*sin(x) + (36 + 57*x + 15*x^2 + x^3)*sinh(x))/48. - Stefano Spezia, May 15 2023
a(n) = A001400(n) + A001400(n-1) + A001400(n-2). - David García Herrero, Aug 26 2024
a(n) = floor((2*n^3 + 24*n^2 + n*(85+3*(-1)^n) + 96) / 96). - Hoang Xuan Thanh, May 24 2025

A318795 Array read by antidiagonals: T(n,k) is the number of inequivalent nonnegative integer n X n matrices with sum of elements equal to k, under row and column permutations.

Original entry on oeis.org

1, 1, 1, 1, 4, 1, 1, 5, 4, 1, 1, 11, 10, 4, 1, 1, 14, 24, 10, 4, 1, 1, 24, 51, 33, 10, 4, 1, 1, 30, 114, 78, 33, 10, 4, 1, 1, 45, 219, 224, 91, 33, 10, 4, 1, 1, 55, 424, 549, 277, 91, 33, 10, 4, 1, 1, 76, 768, 1403, 792, 298, 91, 33, 10, 4, 1, 1, 91, 1352, 3292, 2341, 881, 298, 91, 33, 10, 4, 1

Offset: 1

Andrew Howroyd, Sep 03 2018

			Array begins:
===========================================================
n\k| 1 2  3  4  5   6   7    8    9    10     11     12
---+-------------------------------------------------------
1  | 1 1  1  1  1   1   1    1    1     1      1      1 ...
2  | 1 4  5 11 14  24  30   45   55    76     91    119 ...
3  | 1 4 10 24 51 114 219  424  768  1352   2278   3759 ...
4  | 1 4 10 33 78 224 549 1403 3292  7677  16934  36581 ...
5  | 1 4 10 33 91 277 792 2341 6654 18802  51508 138147 ...
6  | 1 4 10 33 91 298 881 2825 8791 27947  87410 272991 ...
7  | 1 4 10 33 91 298 910 2974 9655 32287 108274 367489 ...
8  | 1 4 10 33 91 298 910 3017 9886 33767 116325 410298 ...
9  | 1 4 10 33 91 298 910 3017 9945 34124 118729 424498 ...
...

Andrew Howroyd, Table of n, a(n) for n = 1..1275
Andrew Howroyd, Additional PARI Programs

Rows 2..7 are A053307, A052365, A052366, A052367, A052372, A052373.
Main diagonal is A007716.
Cf. A214398, A246106, A304942, A318805.

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!)];
Table[M[n-k+1, n-k+1, k], {n, 1, 12}, {k, n, 1, -1}] // Flatten (* Jean-François Alcover, Sep 12 2018, after Andrew Howroyd *)

\\ see also link.
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)={1/prod(j=1, #q, (1-y^lcm(t,q[j]) + O(y*y^k))^gcd(t, q[j]))}
M(m, n, k)={my(s=0); forpart(q=m, s+=permcount(q)*polcoef(polcoef(exp(sum(t=1, n, K(q, t, k)/t*x^t) + O(x*x^n)), n), k)); s/m!}
for(n=1, 10, for(k=1, 12, print1(M(n, n, k), ", ")); print); \\ updated Andrew Howroyd, Mar 29 2020

T(n,k) = T(k,k) for n > k.

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

Vladeta Jovovic, Mar 08 2000

nonn

Also Molien series for group of structure S_3 X S_3 = (Z_3 X Z_3).O_2^+(3) and order 36, corresponding to complete weight enumerators of Hermitian self-dual GF(3)-linear codes over GF(9) containing the all-ones vector.

Andrew Howroyd, Table of n, a(n) for n = 0..1000
G. Nebe, E. M. Rains and N. J. A. Sloane, Self-Dual Codes and Invariant Theory, Springer, Berlin, 2006.
Index entries for Molien series

Row 3 of A318795.

Cf. A002724, A053307, A052366, A052267, A092091.

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 *)

G.f.: -(x^10+2*x^8+x^7+7*x^6-3*x^5+4*x^3+x^2-2*x+1) / ((x^4-x^3+x-1)*(x^3-1)^3*(x+1)^3*(x-1)^5).

Another form for g.f.: u1/u2, where u1 := 1 + x + 2*x^3 + 10*x^4 + 17*x^5 + 19*x^6 + 20*x^7 + 29*x^8 + 37*x^9 + 34*x^10 + 23*x^11 + 12*x^12 + 7*x^13 + 3*x^14 + x^15 u2 := (1-x^2)^4*(1-x^3)^4*(1-x^6);

A054974 Number of nonnegative integer 2 X 2 matrices with no zero rows or columns and with sum of elements equal to n, up to row and column permutation.

Original entry on oeis.org

1, 2, 6, 9, 17, 23, 36, 46, 65, 80, 106, 127, 161, 189, 232, 268, 321, 366, 430, 485, 561, 627, 716, 794, 897, 988, 1106, 1211, 1345, 1465, 1616, 1752, 1921, 2074, 2262, 2433, 2641, 2831, 3060, 3270, 3521, 3752, 4026, 4279, 4577, 4853, 5176, 5476, 5825, 6150

Offset: 2

Vladeta Jovovic, May 28 2000

From Gus Wiseman, Jan 22 2019: (Start)
Also the number of non-isomorphic multiset partitions of weight n with exactly 2 distinct vertices and exactly 2 (not necessarily distinct) edges. For example, non-isomorphic representatives of the a(2) = 1 through a(5) = 9 multiset partitions are:
  {{1}{2}}  {{1}{22}}  {{1}{122}}  {{11}{122}}
            {{2}{12}}  {{11}{22}}  {{1}{1222}}
                       {{12}{12}}  {{11}{222}}
                       {{1}{222}}  {{12}{122}}
                       {{12}{22}}  {{1}{2222}}
                       {{2}{122}}  {{12}{222}}
                                   {{2}{1122}}
                                   {{2}{1222}}
                                   {{22}{122}}
(End)

			There are 9 nonnegative integer 2 X 2 matrices with no zero rows or columns and with sum of elements equal to 5, up to row and column permutation:
[0 1] [0 1] [0 1] [0 1] [0 2] [0 2] [0 2] [0 3] [1 1]
[1 3] [2 2] [3 1] [4 0] [1 2] [2 1] [3 0] [1 1] [1 2].

Colin Barker, Table of n, a(n) for n = 2..1000
Index entries for linear recurrences with constant coefficients, signature (2,1,-4,1,2,-1).

Column k=2 of A321615.

Cf. A007716, A052847, A053307, A323654, A323655, A323656.

gf := -x^2*(x^3-x^2-1)/((x^2-1)^2*(x-1)^2): s := series(gf, x, 101): for i from 2 to 100 do printf(`%d,`,coeff(s,x,i)) od:

Vec(-x^2*(x^3-x^2-1) / ((x^2-1)^2*(x-1)^2) + O(x^60)) \\ Colin Barker, Jan 16 2017

G.f.: -x^2*(x^3-x^2-1) / ((x^2-1)^2*(x-1)^2).
From Colin Barker, Jan 16 2017: (Start)
a(n) = (6 - 6*(-1)^n + (9*(-1)^n-17)*n + 12*n^2 + 2*n^3) / 48.
a(n) = 2*a(n-1) + a(n-2) - 4*a(n-3) + a(n-4) + 2*a(n-5) - a(n-6) for n>7.
(End)

More terms from James Sellers, May 29 2000

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

Vladeta Jovovic, Mar 08 2000

nonn

Andrew Howroyd, Table of n, a(n) for n = 0..1000

Row 4 of A318795.

Cf. A002724, A053307, A052365.

G.f.: (x^34 - 4*x^33 + 6*x^32 - x^31 + 3*x^30 - 11*x^29 + 33*x^28 - 19*x^27 + 81*x^26 - 52*x^25 + 152*x^24 - 36*x^23 + 255*x^22 - 130*x^21 + 367*x^20 - 84*x^19 + 350*x^18 - 94*x^17 + 350*x^16 - 84*x^15 + 367*x^14 - 130*x^13 + 255*x^12 - 36*x^11 + 152*x^10 - 52*x^9 + 81*x^8 - 19*x^7 + 33*x^6 - 11*x^5 + 3*x^4 - x^3 + 6*x^2 - 4*x + 1)/((x^10 + x^9 - x^7 - x^6 + x^4 + x^3 - x - 1)*(x^6 - 1)^2*(x^2 + 1)^3*(x^2 - 1)^4*(x^2 + x + 1)^2*(x + 1)*(x - 1)^9).

A362905 Array read by antidiagonals: T(n,k) is the number of n element multisets of length k vectors over GF(2) that sum to zero.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 4, 2, 1, 1, 1, 8, 5, 3, 1, 1, 1, 16, 15, 11, 3, 1, 1, 1, 32, 51, 50, 14, 4, 1, 1, 1, 64, 187, 276, 99, 24, 4, 1, 1, 1, 128, 715, 1768, 969, 232, 30, 5, 1, 1, 1, 256, 2795, 12496, 11781, 3504, 429, 45, 5, 1, 1, 1, 512, 11051, 93600, 162877, 73440, 10659, 835, 55, 6, 1

Offset: 0

Andrew Howroyd, May 27 2023

Equivalently, T(n,k) is the number multisets with n elements drawn from {0..2^k-1} such that the bitwise-xor of all the elements gives zero.
T(n,k) is the number of equivalence classes of n X k binary matrices with an even number of 1's in each column under permutation of rows.
T(n,k) is the number of equivalence classes of n X k binary matrices under permutation of rows and complementation of columns.

			Array begins:
=========================================
n/k| 0 1  2   3     4      5        6 ...
---+-------------------------------------
0  | 1 1  1   1     1      1        1 ...
1  | 1 1  1   1     1      1        1 ...
2  | 1 2  4   8    16     32       64 ...
3  | 1 2  5  15    51    187      715 ...
4  | 1 3 11  50   276   1768    12496 ...
5  | 1 3 14  99   969  11781   162877 ...
6  | 1 4 24 232  3504  73440  1878976 ...
7  | 1 4 30 429 10659 394383 18730855 ...
  ...

Andrew Howroyd, Table of n, a(n) for n = 0..1325 (first 51 antidiagonals).

Columns k=0..4 are A000012, A004526(n+2), A053307, A362906, A363350.
Rows n=2..3 are A000079, A007581.
Main diagonal is A363351.
Cf. A054724, A340030, A340312, A363349.

A362905[n_,k_]:=(Binomial[2^k+n-1,n]+If[EvenQ[n],(2^k-1)Binomial[2^(k-1)+n/2-1,n/2],0])/2^k;Table[A362905[n-k,k],{n,0,15},{k,n,0,-1}] (* Paolo Xausa, Nov 19 2023 *)

T(n,k)={(binomial(2^k+n-1, n) + if(n%2==0, (2^k-1)*binomial(2^(k-1)+n/2-1,n/2)))/2^k}

T(n,k) = binomial(2^k+n-1, n)/2^k for odd n;
T(n,k) = (binomial(2^k+n-1, n) + (2^k-1)*binomial(2^(k-1)+n/2-1, n/2))/2^k for even n.
G.f. of column k: (1/(1-x)^(2^k) + (2^k-1)/(1-x^2)^(2^(k-1)))/2^k.

A052367 Number of nonnegative integer 5 X 5 matrices with sum of elements equal to n, under row and column permutations.

Original entry on oeis.org

1, 1, 4, 10, 33, 91, 277, 792, 2341, 6654, 18802, 51508, 138147, 359457, 910756, 2240915, 5365106, 12495406, 28353714, 62725603, 135469991, 285904968, 590347527, 1193817552, 2366907846, 4605225266, 8801576140, 16538061290

Offset: 0

Vladeta Jovovic, Mar 08 2000

nonn

Andrew Howroyd, Table of n, a(n) for n = 0..1000

Row 5 of A318795.

Cf. A002724, A053307, A052365, A052366.

G.f.: - (x^86 - 3*x^85 + 9*x^84 + 12*x^83 + 59*x^82 + 116*x^81 + 452*x^80 + 736*x^79 + 2080*x^78 + 3344*x^77 + 7312*x^76 + 11708*x^75 + 21793*x^74 + 32869*x^73 + 55563*x^72 + 79389*x^71 + 123072*x^70 + 168321*x^69 + 243961*x^68 + 319938*x^67 + 438431*x^66 + 553731*x^65 + 724251*x^64 + 885383*x^63 + 1111989*x^62 + 1318149*x^61 + 1600579*x^60 + 1845557*x^59 +
2172889*x^58 + 2444070*x^57 + 2798839*x^56 + 3076865*x^55 + 3436180*x^54 + 3696058*x^53 + 4034590*x^52 + 4250683*x^51 + 4541020*x^50 + 4689359*x^49 + 4909073*x^48 + 4972196*x^47 + 5102026*x^46 + 5069013*x^45 + 5102464*x^44 + 4971700*x^43 + 4909948*x^42 + 4688757*x^41 + 4542211*x^40 + 4249809*x^39 + 4036170*x^38 + 3694857*x^37 + 3438025*x^36 +
3075494*x^35 + 2800760*x^34 + 2442552*x^33 + 2174743*x^32 + 1843864*x^31 + 1602482*x^30 + 1316113*x^29 + 1114023*x^28 + 883313*x^27 + 725930*x^26 + 551915*x^25 + 439662*x^24 + 318308*x^23 + 245205*x^22 + 166823*x^21 + 124009*x^20 + 78506*x^19 + 56071*x^18 + 32361*x^17 + 22208*x^16 + 11357*x^15 + 7673*x^14 + 3221*x^13 + 2294*x^12 + 684*x^11 + 594*x^10 + 59*x^9 + 133*x^8 + 21*x^7 + 18*x^6 - 2*x^4 - 3*x^3 + 9*x^2 - 5*x + 1) divided by (see next line)
((x^20 - 1)*(x^11 - x^10 + x^6 - x^5 + x - 1)*(x^7 - 2*x^6 + x^5 + x^4 - x^3 - x^2 + 2*x - 1)*(x^4 + x^3 + x^2 + x + 1)^4*(x^4 - x^3 + x^2 - x + 1)*(x^4 + x^2 + 1)*(x^2 + 1)^5*(x^2 + x + 1)^5*(x + 1)^11*(x - 1)^22).

cp's OEIS Frontend

A007716 Number of polynomial symmetric functions of matrix of order n under separate row and column permutations.

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A008795 Molien series for 3-dimensional representation of dihedral group D_6 of order 6.

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A100157 Structured rhombic dodecahedral numbers (vertex structure 9).

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A008804 Expansion of 1/((1-x)^2*(1-x^2)*(1-x^4)).

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A318795 Array read by antidiagonals: T(n,k) is the number of inequivalent nonnegative integer n X n matrices with sum of elements equal to k, under row and column permutations.

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A052365 Number of nonnegative integer 3 X 3 matrices with sum of elements equal to n, under row and column permutations.

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A008804 Expansion of 1/((1-x)^2(1-x^2)(1-x^4)).