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 1-4 of 4 results.

A343909 Number of generalized polyforms on the tetrahedral-octahedral honeycomb with n cells.

Original entry on oeis.org

1, 2, 1, 4, 9, 44, 195, 1186, 7385, 49444, 337504, 2353664, 16608401, 118432965, 851396696, 6163949361, 44896941979
Offset: 0

Views

Author

Drake Thomas and Peter Kagey, May 03 2021

Keywords

Comments

This sequence counts "free" polyforms where holes are allowed. This means that two polyforms are considered the same if one is a rigid transformation (translation, rotation, reflection, or a combination thereof) of the other.

Examples

			For n = 1, the a(1) = 2 polyforms are the tetrahedron and the octahedron.
For n = 2, the a(2) = 1 polyform is a tetrahedron and an octahedron connected at a face.
For n = 3, there are a(3) = 4 polyforms with 3 cells:
  - 3 consisting of one octahedron with two tetrahedra, and
  - 1 consisting of two octahedra and one tetrahedron.
For n = 4, there are a(4) = 9 polyforms with 4 cells:
  - 3 with one octahedron and three tetrahedra,
  - 5 with two octahedra and three octahedra, and
  - 1 with three octahedra and one tetrahedron.
For n = 5, there are a(5) = 44 polyforms with 5 cells:
  - 6 with one octahedron and four tetrahedra,
  - 24 with two octahedra and three tetrahedra,
  - 13 with three octahedra and two tetrahedra, and
  - 1 with four octahedra and one tetrahedron.
		

Crossrefs

Row sums of A365970.
Analogous for other honeycombs/tilings: A000105 (square), A000228 (hexagonal), A000577 (triangular), A038119 (cubical), A068870 (tesseractic), A197156 (prismatic pentagonal), A197159 (floret pentagonal), A197459 (rhombille), A197462 (kisrhombille), A197465 (tetrakis square), A309159 (snub square), A343398 (trihexagonal), A343406 (truncated hexagonal), A343577 (truncated square).

Extensions

a(11)-a(16) from Bert Dobbelaere, Jun 10 2025

A384486 Table read by rows: number of connected components of polyhedra in the quarter cubic honeycomb consisting of k tetrahedra and n-k truncated tetrahedra, up to translation, rotation, and reflection of the honeycomb, 0<=k<=n.

Original entry on oeis.org

1, 1, 1, 1, 1, 0, 1, 3, 1, 0, 3, 8, 8, 1, 0, 7, 31, 43, 14, 1, 0, 24, 126, 261, 152, 18, 0, 0, 88, 598, 1543, 1467, 369, 14, 0, 0, 385, 2986, 9276, 12161, 5661, 602, 8, 0, 0, 1713, 15467, 55426, 92723, 65892, 15251, 694, 3, 0, 0, 8112, 81217, 330821, 666705, 646974, 254615, 29830, 551, 1, 0, 0
Offset: 0

Views

Author

Peter Kagey, May 30 2025

Keywords

Comments

Row sums are A384274.

Examples

			Table begins:
 n\k|  0    1     2     3    4   5  6  7
----+------------------------------------
  0 |  1;
  1 |  1,   1;
  2 |  1,   1,    0;
  3 |  1,   3,    1,    0;
  4 |  3,   8,    8,    1,   0;
  5 |  7,  31,   43,   14,   1,  0;
  6 | 24, 126,  261,  152,  18,  0, 0;
  7 | 88, 598, 1543, 1467, 369, 14, 0, 0;
		

Crossrefs

Cf. A365970 (tetrahedral-octahedral honeycomb).

Formula

T(n,0) = A038169(n).

Extensions

More terms from Bert Dobbelaere, Jun 12 2025

A384755 Triangle read by rows: T(n,k) is the number of face-connected components of polyhedra with k prisms and n-k truncated cuboctahedra in the omnitruncated cubic honeycomb up to rotation and reflection, 0 <= k <= n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 3, 7, 10, 2, 12, 41, 76, 46, 4, 61, 335, 809, 777, 232, 13, 407, 3065, 9512, 12863, 7186, 1206, 39, 3226, 30401, 114516, 204143, 172377, 60421, 6548, 155, 28335, 311782, 1381363, 3054599, 3507278, 1975767, 469525, 36081, 637, 262091, 3260971, 16569719, 43731912
Offset: 0

Views

Author

Peter Kagey, Jun 09 2025

Keywords

Comments

Row sums are A384754.

Examples

			0 |   1;
1 |   1,    1;
2 |   1,    2,    1;
3 |   3,    7,   10,     2;
4 |  12,   41,   76,    46,    4;
5 |  61,  335,  809,   777,  232,   13;
6 | 407, 3065, 9512, 12863, 7186, 1206, 39;
		

Crossrefs

Cf. A365970 (tetrahedral-octahedral honeycomb), A384486 (quarter cubic honeycomb), A384782 (rectified cubic honeycomb).

Formula

T(n,0) = A038171(n).

Extensions

More terms from Bert Dobbelaere, Jun 14 2025

A384782 Triangle read by rows: T(n,k) is the number of face-connected polyhedral components consisting of k cuboctahedra and n-k octahedra in the rectified cubic honeycomb up to translation, rotation, and reflection of the honeycomb, 0<=k<=n.

Original entry on oeis.org

1, 1, 1, 0, 1, 1, 0, 3, 4, 2, 0, 3, 18, 12, 7, 0, 6, 60, 126, 75, 23, 0, 3, 165, 751, 1025, 473, 112, 0, 3, 346, 3784, 9414, 8936, 3539, 607, 0, 1, 565, 14112, 66503, 108739, 80531, 27027, 3811, 0, 1, 723, 42420, 362939, 994542, 1204093, 725795, 212122, 25413, 0, 0, 723, 101237, 1586479, 7065791, 13389295, 12792264, 6512671, 1678783, 178083
Offset: 0

Views

Author

Peter Kagey and Bert Dobbelaere, Jun 09 2025

Keywords

Comments

Also the number of face-connected polyhedral components consisting of k truncated cubes and n-k octahedra in the truncated cubic honeycomb up to translation, rotation, and reflection of the honeycomb.
Row sums are given by A384254.

Examples

			Table begins:
   0 | 1;
   1 | 1, 1;
   2 | 0, 1,   1;
   3 | 0, 3,   4,     2;
   4 | 0, 3,  18,    12,      7;
   5 | 0, 6,  60,   126,     75,     23;
   6 | 0, 3, 165,   751,   1025,    473,     112;
   7 | 0, 3, 346,  3784,   9414,   8936,    3539,    607;
   8 | 0, 1, 565, 14112,  66503, 108739,   80531,  27027,   3811;
   9 | 0, 1, 723, 42420, 362939, 994542, 1204093, 725795, 212122, 25413;
		

Crossrefs

Cf. A384254.
Cf. A365970 (tetrahedral-octahedral honeycomb), A384486 (quarter cubic honeycomb), A384755 (omnitruncated cubic honeycomb).

Formula

T(n,n) = A038119(n).
Showing 1-4 of 4 results.