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 1-6 of 6 results.

A366767 Array read by antidiagonals, where each row is the counting sequence of a certain type of fixed polyominoids.

Original entry on oeis.org

1, 0, 1, 0, 1, 2, 0, 1, 0, 2, 0, 1, 0, 2, 2, 0, 1, 0, 2, 4, 2, 0, 1, 0, 2, 12, 6, 1, 0, 1, 0, 2, 38, 22, 0, 1, 0, 1, 0, 2, 126, 88, 0, 2, 1, 0, 1, 0, 2, 432, 372, 0, 6, 2, 1, 0, 1, 0, 2, 1520, 1628, 0, 19, 6, 4, 3, 0, 1, 0, 2, 5450, 7312, 0, 63, 19, 20, 0, 3
Offset: 1

Views

Author

Pontus von Brömssen, Oct 22 2023

Keywords

Comments

See A366766 (corresponding array for free polyominoids) for details.

Examples

			Array begins:
  n\k| 1  2  3   4   5    6     7      8      9      10       11        12
  ---+--------------------------------------------------------------------
   1 | 1  0  0   0   0    0     0      0      0       0        0         0
   2 | 1  1  1   1   1    1     1      1      1       1        1         1
   3 | 2  0  0   0   0    0     0      0      0       0        0         0
   4 | 2  2  2   2   2    2     2      2      2       2        2         2
   5 | 2  4 12  38 126  432  1520   5450  19820   72892   270536   1011722
   6 | 2  6 22  88 372 1628  7312  33466 155446  730534  3466170  16576874
   7 | 1  0  0   0   0    0     0      0      0       0        0         0
   8 | 1  2  6  19  63  216   760   2725   9910   36446   135268    505861
   9 | 1  2  6  19  63  216   760   2725   9910   36446   135268    505861
  10 | 1  4 20 110 638 3832 23592 147941 940982 6053180 39299408 257105146
  11 | 3  0  0   0   0    0     0      0      0       0        0         0
  12 | 3  3  3   3   3    3     3      3      3       3        3         3
		

Crossrefs

Cf. A366766 (free), A366768.
The following table lists some sequences that are rows of the array, together with the corresponding values of D, d, and C (see A366766). Some sequences occur in more than one row. Notation used in the table:
X: Allowed connection.
-: Not allowed connection (but may occur "by accident" as long as it is not needed for connectedness).
.: Not applicable for (D,d) in this row.
!: d < D and all connections have h = 0, so these polyominoids live in d < D dimensions only.
*: Whether a connection of type (g,h) is allowed or not is independent of h.
| | | connections |
| | | g:112223 |
n | D | d | h:010120 | sequence
----+---+---+-------------+----------
1 | 1 | 1 | * -..... | A063524
2 | 1 | 1 | * X..... | A000012
3 |!2 | 1 | * --.... | 2*A063524
4 |!2 | 1 | X-.... | 2*A000012
5 | 2 | 1 | -X.... | 2*A001168
6 | 2 | 1 | * XX.... | A096267
7 | 2 | 2 | * -.-... | A063524
8 | 2 | 2 | * X.-... | A001168
9 | 2 | 2 | * -.X... | A001168
10 | 2 | 2 | * X.X... | A006770
11 |!3 | 1 | * --.... | 3*A063524
12 |!3 | 1 | X-.... | 3*A000012
13 | 3 | 1 | -X.... | A365655
14 | 3 | 1 | * XX.... | A365560
15 |!3 | 2 | * ----.. | 3*A063524
16 |!3 | 2 | X---.. | 3*A001168
17 | 3 | 2 | -X--.. | A365655
18 | 3 | 2 | * XX--.. | A075678
19 |!3 | 2 | --X-.. | 3*A001168
20 |!3 | 2 | X-X-.. | 3*A006770
21 | 3 | 2 | -XX-.. | A365996
22 | 3 | 2 | XXX-.. | A365998
23 | 3 | 2 | ---X.. | A366000
24 | 3 | 2 | X--X.. | A366002
25 | 3 | 2 | -X-X.. | A366004
26 | 3 | 2 | XX-X.. | A366006
27 | 3 | 2 | * --XX.. | A365653
28 | 3 | 2 | X-XX.. | A366008
29 | 3 | 2 | -XXX.. | A366010
30 | 3 | 2 | * XXXX.. | A365651
31 | 3 | 3 | * -.-..- | A063524
32 | 3 | 3 | * X.-..- | A001931
33 | 3 | 3 | * -.X..- | A039742
34 | 3 | 3 | * X.X..- |
35 | 3 | 3 | * -.-..X | A039741
36 | 3 | 3 | * X.-..X |
37 | 3 | 3 | * -.X..X |
38 | 3 | 3 | * X.X..X |
39 |!4 | 1 | * --.... | 4*A063524
40 |!4 | 1 | X-.... | 4*A000012
41 | 4 | 1 | -X.... | A366341
42 | 4 | 1 | * XX.... | A365562
43 |!4 | 2 | * -----. | 6*A063524
44 |!4 | 2 | X----. | 6*A001168
45 | 4 | 2 | -X---. | A366339
46 | 4 | 2 | * XX---. | A366335
47 |!4 | 2 | --X--. | 6*A001168
48 |!4 | 2 | X-X--. | 6*A006770

A365561 Number of free n-polysticks (or polyedges) in 4 dimensions.

Original entry on oeis.org

1, 2, 7, 31, 199, 1651, 16648
Offset: 1

Views

Author

Pontus von Brömssen, Sep 09 2023

Keywords

Crossrefs

42nd row of A366766.
Sum of first four columns of A365566.
Cf. A019988 (2 dimensions), A365559 (3 dimensions), A365562 (fixed), A365563 (5 dimensions), A365565 (arbitrary dimension).

A365560 Number of fixed n-polysticks (or polyedges) in 3 dimensions.

Original entry on oeis.org

3, 15, 95, 681, 5277, 43086, 365313, 3186444, 28414802, 257908020, 2375037477, 22136623447, 208438845633, 1979867655945, 18948498050586, 182549617674339, 1768943859449895, 17230208981859485
Offset: 1

Views

Author

Pontus von Brömssen, Sep 09 2023

Keywords

Crossrefs

Cf. A096267 (2 dimensions), A365559 (free), A365562 (4 dimensions), A365564 (5 dimensions).
14th row of A366767.

Extensions

a(9)-a(12) from John Mason, Mar 06 2025
a(13) from John Mason, Mar 23 2025
a(14)-a(18) from Mertens & Moore added by Andrei Zabolotskii, Jun 27 2025

A366335 Number of fixed (4,2)-polyominoids with n cells.

Original entry on oeis.org

6, 60, 916, 16698, 336210, 7218768, 162185112, 3769221330, 89924613880
Offset: 1

Views

Author

Pontus von Brömssen, Oct 07 2023

Keywords

Comments

A (D,d)-polyominoid is a connected set of d-dimensional unit cubes with integer coordinates in D-dimensional space, where two cubes are connected if they share a (d-1)-dimensional facet. For example, (3,2)-polyominoids are normal polyominoids (A075678), (D,D)-polyominoids are D-dimensional polyominoes (A001168, A001931, A151830, ...), and (D,1)-polyominoids are polysticks in D dimensions (A096267, A365560, A365562, ...).

Crossrefs

Cf. A366334 (free).
46th row of A366767.
Fixed (D,d)-polyominoids:
D\d| 1 2 3 4
---+--------------------------------
1 | A000012

Extensions

a(7)-a(9) from John Mason, Jul 05 2025

A365564 Number of fixed n-polysticks (or polyedges) in 5 dimensions.

Original entry on oeis.org

5, 45, 525, 7065, 104097, 1632915, 26817465, 456137580, 7975932715, 142619162000, 2597695379665, 48053332283700, 900703198101845
Offset: 1

Views

Author

Pontus von Brömssen, Sep 09 2023

Keywords

Crossrefs

Cf. A096267 (2 dimensions), A365560 (3 dimensions), A365562 (4 dimensions), A365563 (free).

Extensions

a(7)-a(13) from Mertens and Moore (a(7)-a(12) computed from Appendix A, a(13) from the caption of Table 1), added by Pontus von Brömssen, Jun 29 2025

A385581 Square array read by antidiagonals: T(n,d) is the number of fixed d-dimensional polysticks of size n.

Original entry on oeis.org

1, 2, 1, 3, 6, 1, 4, 15, 22, 1, 5, 28, 95, 88, 1, 6, 45, 252, 681, 372, 1, 7, 66, 525, 2600, 5277, 1628, 1, 8, 91, 946, 7065, 29248, 43086, 7312, 1, 9, 120, 1547, 15696, 104097, 349132, 365313, 33466, 1, 10, 153, 2360, 30513, 285828, 1632915, 4351944, 3186444, 155446, 1
Offset: 1

Views

Author

Pontus von Brömssen, Jul 04 2025

Keywords

Comments

The first 17 antidiagonals are from Mertens and Moore (2018), either directly from Table 1 or computed using the perimeter polynomials in Appendix A. T(14,5) is the only unknown value in the 18th antidiagonal.
T(13,6) = 14054816418877200 (Mertens and Moore).

Examples

			Table begins:
  n\d| 1     2       3        4         5          6          7           8
  ---+---------------------------------------------------------------------
  1  | 1     2       3        4         5          6          7           8
  2  | 1     6      15       28        45         66         91         120
  3  | 1    22      95      252       525        946       1547        2360
  4  | 1    88     681     2600      7065      15696      30513       53936
  5  | 1   372    5277    29248    104097     285828     661549     1356384
  6  | 1  1628   43086   349132   1632915    5551480   15314936    36449288
  7  | 1  7312  365313  4351944  26817465  113045832  372033993  1028383408
  8  | 1 33466 3186444 56062681 456137580 2386821009 9377038237 30118187174
		

Crossrefs

Cf. A000384 (row n=2), A385291 (polyominoes), A385582, A385583 (free).
Columns: A096267 (d=2), A365560 (d=3), A365562 (d=4), A365564 (d=5).

Formula

T(n,d) = Sum_{k=1..d} binomial(n,k)*A385582(n,k) (with A385582(n,k) = 0 if d > n).
Showing 1-6 of 6 results.