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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A306096 Number of plane partitions of n where parts are colored in (at most) 6 colors.

Original entry on oeis.org

1, 6, 78, 726, 7278, 62574, 586878, 4889166, 42892710, 354335982, 2976581670, 23990771094, 197564663094, 1565310230790, 12548473437822, 98526949264374, 776195574339102, 6008457242324814, 46729763436714126, 357901583160822990, 2748384845416097718
Offset: 0

Views

Author

M. F. Hasler, Oct 16 2018

Keywords

Comments

a(0) = 1 corresponds to the empty sum, in which all terms are colored in one among six given colors, since there is no term at all.

Examples

			For n = 1, there is only the partition [1], which can be colored in any of the six colors, whence a(1) = 6.
For n = 2, there are the partitions [2], [1,1] and [1;1]. Adding colors, this yields a(2) = 6 + 36 + 36 = 78 distinct possibilities.
		

Crossrefs

Column 6 of A306100 and A306101. See A306099, A306093, A306094, A306095 for columns 2, 3, 4 and 5.

Programs

  • PARI
    a(n)=sum(k=1,n,A091298(n,k)*6^k,!n)

Formula

a(n) = Sum_{k=1..n} A091298(n,k)*6^k, for n > 0.

A096597 Triangle read by rows: T[n,m] = number of plane partitions of n whose 3-dimensional Ferrers plot just fits inside an m X m X m box, i.e., with Max[parts, rows, columns] = m.

Original entry on oeis.org

1, 0, 3, 0, 3, 3, 0, 4, 6, 3, 0, 3, 12, 6, 3, 0, 3, 21, 15, 6, 3, 0, 1, 31, 30, 15, 6, 3, 0, 1, 42, 60, 33, 15, 6, 3, 0, 0, 54, 102, 69, 33, 15, 6, 3, 0, 0, 64, 175, 132, 72, 33, 15, 6, 3, 0, 0, 73, 270, 246, 141, 72, 33, 15, 6, 3, 0, 0, 81, 417, 432, 276, 144, 72, 33, 15, 6, 3, 0, 0, 83
Offset: 1

Views

Author

Wouter Meeussen, Aug 14 2004

Keywords

Comments

Row sums equal A000219 (plane partitions).
Conjecture: the last (floor(n/2)) terms of each row read backwards are 3*A091360 (partial sums of A000219).
Björner & Stanley (2010) give in eq.(3.7) MacMahon's generating function pp(r,s,t) for the number of plane partitions with rows <= r, columns <= s, parts <= t. For r = s = t = m, it simplifies to the g.f. f(m) given in formula. A g.f. for column m of this table is then f(m) - f(m-1). - M. F. Hasler, Sep 26 2018

Examples

			The table starts:
  n : T[n,1..n]
  1 : [1]
  2 : [0, 3]
  3 : [0, 3,  3]
  4 : [0, 4,  6,   3]
  5 : [0, 3, 12,   6,  3]
  6 : [0, 3, 21,  15,  6,  3]
  7 : [0, 1, 31,  30, 15,  6,  3]
  8 : [0, 1, 42,  60, 33, 15,  6, 3]
  9 : [0, 0, 54, 102, 69, 33, 15, 6, 3]
etc.
T[5,2] = 3 counts the plane partitions {{2,1},{2}}, {{2,1},{1,1}} and {{2,2},{1}}.
		

Crossrefs

Programs

  • Mathematica
    (* see A089924 for "planepartitions[]" *) Table[Rest@CoefficientList[Plus@@(x ^ Max[Flatten[ # ], Length[ # ], Max[Length/@# ]]&/@ planepartitions[n]), x], {n, 19}]
  • PARI
    A096597_row(n,c=vector(n))={for(i=1,#n=PlanePartitions(n),c[vecmax([#n[i], #n[i][1], n[i][1][1]])]++);c} \\ See A091298 for PlanePartitions().
    {A096597(n,m,x=(O('x^n)+1)*'x,f(r)=prod(k=1,2*r-1,((1-x^(k+r))/(1-x^k))^min(k,2*r-k)))=polcoeff(f(m)-f(m-1),n)} \\ Replace "polcoeff(...,n)" by "Vec(...)" to get the whole column m up to row n (for "Vec(...,-n)", padded with leading 0's). - M. F. Hasler, Sep 26 2018

Formula

k-th column is CoefficientList[Series[qMacMahon[k]-qMacMahon[k-1], {q, 0, 3^k}], q] with qMacMahon[n_Integer]:=Product[qan[i+j+k-1]/qan[i+j+k-2], {i, n}, {j, n}, {k, n}] and qan[n_]:=(q^n-1)/(q-1). - Wouter Meeussen, Aug 28 2004
From M. F. Hasler, Sep 26 2018: (Start)
G.f. of column m: f(m)-f(m-1), where f(m) = Product_{k=1..2*m-1} ((1-X^(k+m))/(1-X^k))^min(k,2*m-k).
From the definition, we have T[n,m] = 0 if n > m^3.
Columns and reversed rows converge to 3*A091360: T[m+k,m] = T[2m,2m-k] = 3*A091360(k) for 0 <= k < m-1. (End)

Extensions

Edited by M. F. Hasler, Sep 24 2018

A306098 Number of equivalence classes, modulo transposition, of non-symmetric plane partitions of n.

Original entry on oeis.org

0, 0, 1, 2, 5, 10, 21, 39, 74, 133, 239, 415, 719, 1216, 2048, 3393, 5586, 9087, 14695, 23530, 37462, 59172, 92947, 145024, 225123, 347421, 533614, 815378, 1240410, 1878302, 2832586, 4253800, 6363760, 9483831, 14083418, 20839900, 30735490, 45181303, 66210373, 96730731
Offset: 0

Views

Author

M. F. Hasler, Sep 26 2018

Keywords

Comments

A plane partition of n is a matrix of nonnegative integers that sum up to n, and such that A[i,j] >= A[i+1,j], A[i,j] >= A[i,j+1] for all i,j. We can consider A of infinite size but there are at most n nonzero rows and columns and we can ignore empty rows or columns. It is symmetric iff A = transpose(A), or A[i,j] = A[j,i] for all i,j.
For any n, we have the total number of plane partitions of n, A000219(n) = A005987(n) + 2*a(n), where A005987 is the number of symmetric plane partitions. For any of the non-symmetric plane partitions, its transpose is a different plane partition of n. So the difference A000219 - A005987 is always even, equal to twice a(n).

Examples

			The only plane partition of n = 0 is the empty partition []; by convention we do consider it to be symmetric (like a 0 X 0 matrix), so there is no non-symmetric plane partition of 0: a(0) = 0.
The only plane partition of n = 1 is the partition [1] which is symmetric, so there's again no non-symmetric plane partition of 1: a(1) = 0.
For n = 2 we have the partitions [2], [1 1] and [1; 1] (where ; denotes the end of a row). The first one is symmetric, the two others aren't, but are the transpose of each other, so a(2) = 1.
For n = 3 we have the partitions [3], [2 1], [2; 1], [1 1; 1 0], [1 1 1], [1; 1; 1]. The first and the fourth are symmetric, second and third, and fifth and sixth are non-symmetric, and pairwise the transpose of each other, so a(3) = 2.
		

Crossrefs

Programs

  • PARI
    a(n)=#select(t->(t=matconcat(t~))~!=t,PlanePartitions(n))/2 \\ For illustrative purpose: remove "#" to see the list. See A091298 for PlanePartitions(). More efficiently: A306098(n)=(A000219(n)-A005987(n))/2

Formula

a(n) = (A000219(n) - A005987(n))/2.

A319648 Total number of parts in all plane partitions of n.

Original entry on oeis.org

0, 1, 5, 14, 38, 85, 196, 401, 830, 1615, 3119, 5802, 10718, 19246, 34276, 59889, 103656, 176801, 299025, 499732, 828638, 1360696, 2218128, 3586194, 5759839, 9184715, 14557974, 22929745, 35916469, 55942850, 86695329, 133671740, 205144324, 313380895, 476667370
Offset: 0

Views

Author

Alois P. Heinz, Sep 25 2018

Keywords

Examples

			The plane partitions of 2 are [2], [1 1] and [1; 1]. There is a total of a(2) = 5 parts. - _M. F. Hasler_, Sep 27 2018
		

Crossrefs

Row sums of A092288.
Cf. A000219.

Programs

  • PARI
    A319648(n)={vecsum(apply(pp->vecsum(apply(p->#p,pp)),PlanePartitions(n)))} \\ See A091298 for PlanePartitions(). For illustration mainly, becomes slow for n > 15. - M. F. Hasler, Sep 27 2018
    
  • PARI
    M319648=[]; A319648(n,L=0,s)={if(L, n>1||return([1,1]); #L>2||(s=setsearch(M319648,[[n,L],[]],1))>#M319648|| M319648[s][1]!=[n,L]|| return(M319648[s][2]); my(S=[1,n]); for(m=2,n, forpart(P=m, vecmin(L-Vecrev(P,#L))<0&&next; S+=if(mA319648(n-m,Vecrev(P))*[1,#P;0,1],[1,#P]),L[1],#L)); #L>2|| M319648=setunion(M319648,[[[n,L],S]]); S, my(S=n); n>1&& forpart(P=n,S+=#P); for(m=2,n-1,forpart(P=m,S+=A319648(n-m,Vecrev(P))*[#P,1]~));S)} \\ M. F. Hasler, Sep 30 2018

Formula

a(n) = Sum_{k=1..n} k*A091298(n,k). - M. F. Hasler, Sep 27 2018
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