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.

Showing 1-10 of 11 results. Next

A096573 Number of fixed points of mirroring operation on solid partitions.

Original entry on oeis.org

1, 2, 4, 8, 13, 24, 39, 68, 110, 182, 288, 468, 728, 1150, 1770, 2751, 4175, 6388, 9597, 14495, 21571, 32200, 47498
Offset: 1

Views

Author

Wouter Meeussen, Jun 27 2004

Keywords

Comments

Uses function "solidformBTK" from link below.

Examples

			Solid partition [{{3, 1, 1, 1}, {3}}, {{2, 1}}, {{1}}, {{1}}, {{1}}] mirrors into [{{3, 3}, {1}, {1}, {1}}, {{2}, {1}}, {{1}}, {{1}}, {{1}}] by mirroring each layer as a plane partition.
		

Crossrefs

Programs

  • Mathematica
    Tr/@Table[Count[solidformBTK[par],arg_z/;flip[arg]==arg],{n,20},{par,IntegerPartitions[n]}] (* Wouter Meeussen, Feb 05 2025  *)

Extensions

a(16)-a(23) from Wouter Meeussen, Feb 05 2025

A096574 Number of asymmetric solid partitions under mirroring operation.

Original entry on oeis.org

0, 1, 3, 9, 23, 58, 134, 308, 677, 1470, 3106, 6479, 13260, 26827, 53516
Offset: 1

Views

Author

Wouter Meeussen, Jun 27 2004

Keywords

Comments

Uses function "solidformBTK" from link above.

Examples

			Solid partition [{{3, 1, 1, 1}, {3}}, {{2, 1}}, {{1}}, {{1}}, {{1}}] mirrors into [{{3, 3}, {1}, {1}, {1}}, {{2}, {1}}, {{1}}, {{1}}, {{1}}] by mirroring each layer as a plane partition.
		

Crossrefs

Formula

a(n) = (A000293(n) - A096573(n))/2.

A096577 Number of fixed points of solid partitions under 'time-lapse' operation.

Original entry on oeis.org

1, 0, 0, 0, 1, 0, 1, 0, 2, 0, 2, 0, 2, 0, 4, 1, 5, 0, 7, 1, 7, 0, 14
Offset: 1

Views

Author

Wouter Meeussen, Jun 27 2004

Keywords

Comments

Operation 'time lapse', or 'lapse', L, operates on a solid partition by creating a new one, layer by layer. Layer k is defined by its 3-dimensional-Ferrers plot, equal to the (existence of) elements of the solid partition with value >= k. As if taking a time-lapse picture of the solid partition, filtering out elements less than k and projecting the resulting structure (filled with ones) to the base plane. Given there are three planes to project into, together with the starting solid partition, that makes four 'isomers'.

Examples

			Solid partition [{{3,1,1,1},{3}},{{2,1}},{{1}},{{1}},{{1}}] lapses (L) into
[{{4,1},{2},{1},{1},{1}},{{1,1},{1}},{{1,1}}], then into
[{{2,1,1,1,1},{2,1},{2}},{{1,1}},{{1}},{{1}}], further into
[{{5,2,1},{2},{1},{1}},{{1,1,1}}] and returns after L^4 to
[{{3,1,1,1},{3}},{{2,1}},{{1}},{{1}},{{1}}].
		

Crossrefs

Programs

  • Mathematica
    (* See link above. *)
    Tr/@Table[Count[solidformBTK[par],arg_z/;lapse[arg]==arg],{n,20},{par,IntegerPartitions[n]}] (* Wouter Meeussen, Feb 05 2025 *)

Extensions

a(16)-a(23) from Wouter Meeussen, Mar 19 2025

A119266 Number of 3-dimensional partitions of n up to conjugacy.

Original entry on oeis.org

1, 1, 1, 2, 4, 7, 13, 25, 49, 93, 181, 351, 687, 1332, 2591, 5003, 9644, 18462, 35208, 66721, 125840, 235914, 440020, 816122, 1505986, 2764303, 5048960, 9176069
Offset: 0

Views

Author

Keywords

Comments

Partitions are considered as generalized Ferrers diagrams; any permutation of the axes produces a conjugate.

Crossrefs

Formula

a(n) = (A000293(n) + 6*A096573(n) + 8*A096575(n) + 3*A382247(n) + 6*A096577(n))/24 by Burnside's lemma. - Wouter Meeussen, Mar 19 2025

Extensions

a(9)-a(23) from Max Alekseyev, May 15 2006
a(24)-a(27) from Max Alekseyev, Mar 20 2025

A096576 Number of solid partitions asymmetric under rotation operation.

Original entry on oeis.org

0, 1, 3, 8, 19, 46, 101, 226, 486, 1038, 2163, 4471, 9077, 18260, 36258
Offset: 1

Views

Author

Wouter Meeussen, Jun 27 2004

Keywords

Comments

Rotation has permutation cycle length 1 or 3. Uses function "solidformBTK" from link above.

Examples

			Solid partition [{{3, 1, 1, 1}, {3}}, {{2, 1}}, {{1}}, {{1}}, {{1}}] rotates into [{{4, 1}, {1, 1}, {1, 1}}, {{2}, {1}}, {{1}}, {{1}}, {{1}}] by rotating each layer as a plane partition.
		

Crossrefs

Programs

Formula

a(n) = (A000293(n) - A096575(n))/3.

A096578 Number of solid partitions with period (cycle length) two under 'time-lapse' operation.

Original entry on oeis.org

0, 0, 1, 1, 1, 2, 3, 6, 7, 11, 15, 25, 33, 48, 65
Offset: 1

Views

Author

Wouter Meeussen, Jun 27 2004

Keywords

Comments

Operation 'time lapse', or 'lapse', L, operates on a solid partition by creating a new one, layer by layer. Layer k is defined by its 3-dimensional-Ferrers plot, equal to the (existence of) elements of the solid partition with value >= k. As if taking a time-lapse picture of the solid partition, filtering out elements less than k and projecting the resulting structure (filled with ones) to the base plane. Given there are three plane to project into, together with the starting solid partition, that makezs four 'isomers'.

Examples

			Solid partition [{{3,1,1,1},{3}},{{2,1}},{{1}},{{1}},{{1}}] lapses (L) into
[{{4,1},{2},{1},{1},{1}},{{1,1},{1}},{{1,1}}], then into
[{{2,1,1,1,1},{2,1},{2}},{{1,1}},{{1}},{{1}}], further into
[{{5,2,1},{2},{1},{1}},{{1,1,1}}] and returns after L^4 to
[{{3,1,1,1},{3}},{{2,1}},{{1}},{{1}},{{1}}]
		

Crossrefs

Programs

  • Mathematica
    (* See link above. *)

A096581 Number of solid partitions non-symmetric under L^2 (L= 'time-lapse' symmetry operation) on solid partitions.

Original entry on oeis.org

0, 2, 4, 12, 28, 68, 150, 336, 724, 1550, 3234, 6688, 13590, 27354, 54334
Offset: 1

Views

Author

Wouter Meeussen, Jun 27 2004

Keywords

Examples

			Solid partition [{{3,1,1,1},{3}},{{2,1}},{{1}},{{1}},{{1}}] lapses (L) into
[{{4,1},{2},{1},{1},{1}},{{1,1},{1}},{{1,1}}], then into
[{{2,1,1,1,1},{2,1},{2}},{{1,1}},{{1}},{{1}}], further into
[{{5,2,1},{2},{1},{1}},{{1,1,1}}] and returns after L^4 to
[{{3,1,1,1},{3}},{{2,1}},{{1}},{{1}},{{1}}]
		

Crossrefs

Programs

  • Mathematica
    (* See link above. *)

Formula

By definition, A000293(n) = A096580(n) + 2*a(n).

A096322 Limiting sequence formed by rows of A094504 read backwards: rightmost floor(n/2)+1 terms of row n in table A094504.

Original entry on oeis.org

1, 3, 9, 25, 66, 165, 402, 943, 2163, 4835, 10598, 22785, 48215, 100470, 206620, 419662, 842928, 1675487, 3298688, 6436210, 12453352, 23905923, 45550529, 86180937, 161964145, 302447657
Offset: 1

Views

Author

Wouter Meeussen, Jun 27 2004

Keywords

Comments

Same sequence, multiplied by four, occurs in A096272.
a(n) is the number of solid partitions with layer structure an integer partition of (2n-2) in exactly (n-1) parts. - Wouter Meeussen, Mar 12 2025

Examples

			For n=3 the a(3)= 9 solid partitions are generated by the integer partitions of (2n-2) in exactly (n-1) parts with parts =1 and duplicate parts deleted, so just {3} and {2} :
 z[{{3}}], z[{{2,1}}], z[{{1,1,1}}], z[{{2},{1}}], z[{{1,1},{1}}], z[{{1},{1},{1}}] and  z[{{2}}], z[{{1,1}}], z[{{1},{1}}]
		

Crossrefs

Extensions

Extended to n=26, Wouter Meeussen, May 23 2025

A097507 24*a(n) counts the solid partitions of n that have no symmetry under any single or combined operations built from mirroring (F), rotation (T) or 4-D rotation (L).

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 5, 14, 36, 88, 203, 447, 957, 2000, 4095, 8234, 16326, 31946, 61826, 118451, 224936, 423651, 792003, 1470365, 2712239, 4972772, 9065500, 16437451, 29651289, 53225532, 95094532, 169135038
Offset: 1

Views

Author

Wouter Meeussen, Sep 19 2004

Keywords

Crossrefs

Extensions

More terms added by Suresh Govindarajan, Jun 07 2013

A097516 a(n) counts the solid partitions of n that are symmetric under all of the operations mirroring (F), rotation (T) and 4-D rotation (L).

Original entry on oeis.org

1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 2, 1, 1, 0, 2, 1, 1, 0, 2, 1, 1, 0, 3, 1, 1, 0, 4, 2, 2, 0, 4, 2, 3, 1, 4, 2, 3, 1, 6, 3, 3, 1, 7, 5, 5, 2, 7, 5, 6, 4, 7, 5, 6, 4, 9, 6, 8, 5, 10, 8, 12, 9, 11, 8, 13, 12, 13, 11, 13, 12, 15, 14, 17, 15, 16, 18, 22, 21, 18, 19, 23, 25, 20, 23, 27, 28, 22, 26, 34, 37, 26, 32, 39, 47, 31, 40
Offset: 1

Views

Author

Wouter Meeussen, Sep 19 2004

Keywords

Examples

			The totally symmetric solid partitions up to n=15 are:
[{{1}}]
[{{2,1}, {1}}, {{1}}]
[{{3,1,1}, {1}, {1}}, {{1}}, {{1}}]
[{{2,2}, {2,1}}, {{2,1}, {1}}]
[{{4,1,1,1}, {1}, {1}, {1}}, {{1}}, {{1}}, {{1}}]
[{{3,2,1}, {2,1}, {1}}, {{2,1}, {1}}, {{1}}] and
[{{2,2}, {2,2}}, {{2,2}, {2,1}}]
A list of weakly decreasing 4-tuples is enough to specify a totally symmetric solid partition.  First, think of a solid partition as a set of points in a 4-dimensional integral lattice in the standard way.  (Here I take the point (1, 1, 1, 1)—rather than (0, 0, 0, 0)—to represent the sole partition of 1.  Thus, all points have coordinates which are strictly positive.)
Now, associate to a weakly decreasing 4-tuples the smallest totally symmetric solid partition containing each of the listed 4-tuples as points.  For instance, the partition, call it p, which is represented by the list:
{(3, 1, 1, 1), (2, 2, 2, 1)}
is found by first noting that all points of the form (a, b, c, d) where a<=3, b<=1, c<=1, d<=1 (i.e the points (2, 1, 1, 1) and (1, 1, 1, 1)) must be points of p.  Similarly, all points (x, y, z, w) with x<=2, y<=2, z<=2, w<=1, must be points of p.  Furthermore all permutations of the coordinates of a point of p must also give a point of p by symmetry: E.g., since (2, 2, 1, 1) is a point of p, so are (2, 1, 2, 1), (2, 1, 1, 2), (1, 2, 2, 1), etc.  If we count all the points of p, we see p partitions 19.
Using this notation, we may represent the 5 totally symmetric solid partitions of 62 as:
1.  {(3, 3, 2, 1), (2, 2, 2, 2)}
2.  {(5, 1, 1, 1), (3, 3, 1, 1), (3, 2, 2, 2)}
3.  {(9, 1, 1, 1), (3, 3, 1, 1), (2, 2, 2, 2)}
4.  {(6, 1, 1, 1), (3, 3, 1, 1), (3, 2, 2, 1), (2, 2, 2, 2)}
5.  {(6, 1, 1, 1), (4, 2, 1, 1), (3, 3, 1, 1), (2, 2, 2, 2)}
		

Crossrefs

Extensions

a(16)-a(32) from Suresh Govindarajan, Jun 07 2013
More terms and example text added by Graham H. Hawkes, Dec 24 2013
Showing 1-10 of 11 results. Next