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 1-8 of 8 results.

A350820 Array read by antidiagonals: T(m,n) is the number of minimum dominating sets in the grid graph P_m X P_n.

Original entry on oeis.org

1, 2, 2, 1, 6, 1, 4, 3, 3, 4, 3, 12, 10, 12, 3, 1, 2, 29, 29, 2, 1, 8, 17, 1, 2, 1, 17, 8, 4, 2, 2, 52, 52, 2, 2, 4, 1, 20, 11, 92, 22, 92, 11, 20, 1, 13, 2, 46, 2, 13, 13, 2, 46, 2, 13, 5, 24, 1, 4, 3, 288, 3, 4, 1, 24, 5, 1, 2, 3, 324, 344, 34, 34, 344, 324, 3, 2, 1
Offset: 1

Views

Author

Andrew Howroyd, Jan 17 2022

Keywords

Comments

The domination number of the grid graphs is tabulated in A350823.

Examples

			Table begins:
===================================
m\n | 1  2  3  4   5   6  7   8
----+------------------------------
  1 | 1  2  1  4   3   1  8   4 ...
  2 | 2  6  3 12   2  17  2  20 ...
  3 | 1  3 10 29   1   2 11  46 ...
  4 | 4 12 29  2  52  92  2   4 ...
  5 | 3  2  1 52  22  13  3 344 ...
  6 | 1 17  2 92  13 288 34   2 ...
  7 | 8  2 11  2   3  34  2  34 ...
  8 | 4 20 46  4 344   2 34  52 ...
  ...
		

Crossrefs

Rows 1..4 are A347633, A347558, A350821, A350822.
Main diagonal is A347632.
Cf. A218354 (dominating sets), A286847 (minimal dominating sets), A303293, A350815, A350823.

Formula

T(m,n) = T(n,m).

A286849 Array read by antidiagonals: T(m,n) = number of minimal dominating sets in the n X m king graph.

Original entry on oeis.org

1, 2, 2, 2, 4, 2, 4, 6, 6, 4, 4, 16, 12, 16, 4, 7, 20, 36, 36, 20, 7, 9, 52, 64, 256, 64, 52, 9, 13, 80, 204, 400, 400, 204, 80, 13, 18, 176, 446, 2704, 971, 2704, 446, 176, 18, 25, 296, 1184, 6400, 6486, 6486, 6400, 1184, 296, 25
Offset: 1

Views

Author

Andrew Howroyd, Aug 01 2017

Keywords

Examples

			Array begins:
===========================================================
m\n|  1   2    3     4      5       6        7         8
---|-------------------------------------------------------
1  |  1   2    2     4      4       7        9        13...
2  |  2   4    6    16     20      52       80       176...
3  |  2   6   12    36     64     204      446      1184...
4  |  4  16   36   256    400    2704     6400     30976...
5  |  4  20   64   400    971    6486    22177    112317...
6  |  7  52  204  2704   6486   85405   351503   3082745...
7  |  9  80  446  6400  22177  351503  1997448  21587536...
8  | 13 176 1184 30976 112317 3082745 21587536 360584008...
...
		

Crossrefs

Rows 1-2 are A253413, A286850.
Main diagonal is A286881.
Cf. A218663 (dominating sets), A245013 (independent), A286870 (irredundant).
Cf. A286847 (grid graph).

A286868 Array read by antidiagonals: T(m,n) = number of irredundant sets in the grid graph P_m X P_n.

Original entry on oeis.org

2, 3, 3, 5, 11, 5, 9, 26, 26, 9, 15, 79, 113, 79, 15, 26, 224, 548, 548, 224, 26, 44, 640, 2513, 4481, 2513, 640, 44, 76, 1828, 11826, 34049, 34049, 11826, 1828, 76, 130, 5225, 55136, 265227, 425926, 265227, 55136, 5225, 130
Offset: 1

Views

Author

Andrew Howroyd, Aug 02 2017

Keywords

Examples

			Array begins:
=============================================================
m\n|  1    2     3       4        5          6           7
---|---------------------------------------------------------
1  |  2    3     5       9       15         26          44...
2  |  3   11    26      79      224        640        1828...
3  |  5   26   113     548     2513      11826       55136...
4  |  9   79   548    4481    34049     265227     2052725...
5  | 15  224  2513   34049   425926    5467052    69724154...
6  | 26  640 11826  265227  5467052  116003176  2441933224...
7  | 44 1828 55136 2052725 69724154 2441933224 84850904785...
...
		

Crossrefs

Row 1 is A286887.
Main diagonal is A286869.
Cf. A286847 (minimal dominating sets).
Cf. A286870 (king graph).

A290379 Number of minimal dominating sets in the n-ladder graph.

Original entry on oeis.org

2, 6, 7, 18, 39, 75, 155, 310, 638, 1295, 2624, 5339, 10853, 22069, 44836, 91134, 185259, 376542, 765331, 1555567, 3161843, 6426646, 13062506, 26550391, 53965428, 109688223, 222948193, 453156469, 921069708, 1872133138, 3805230243, 7734373962, 15720610559
Offset: 1

Views

Author

Eric W. Weisstein, Jul 28 2017

Keywords

Crossrefs

Row 2 of A286847.

Programs

  • Magma
    I:=[2,6,7,18,39,75,155,310,638,1295,2624]; [n le 11 select I[n] else Self(n-2)+3*Self(n-3)+4*Self(n-4)+4*Self(n-5)+Self(n-6)+2*Self(n-7)+3*Self(n-8)+5*Self(n-9)+4*Self(n-10)+2*Self(n-11): n in [1..40]]; // Vincenzo Librandi, Aug 04 2017
  • Mathematica
    Table[-RootSum[-2 - 4 # - 5 #^2 - 3 #^3 - 2 #^4 - #^5 - 4 #^6 - 4 #^7 - 3 #^8 - #^9 + #^11 &, 621827501801 #^n - 301456826961 #^(n + 1) + 280366986955 #^(n + 2) - 1253389979482 #^(n + 3) + 843186094854 #^(n + 4) - 87555893434 #^(n + 5) + 236346312907 #^(n + 6) - 504072574383 #^(n + 7) + 231943645265 #^(n + 8) - 618185916584 #^(n + 9) + 290649224768 #^(n + 10) &]/2097121971853, {n, 20}] (* Eric W. Weisstein, Aug 04 2017 *)
    LinearRecurrence[{0, 1, 3, 4, 4, 1, 2, 3, 5, 4, 2}, {2, 6, 7, 18, 39, 75, 155, 310, 638, 1295, 2624}, 20] (* Eric W. Weisstein, Aug 04 2017 *)
    CoefficientList[Series[((1 + x) (2 + 4 x + x^2 + 5 x^3 + x^4 + 3 x^5 + 5 x^6 + 3 x^7 + 2 x^8 + 2 x^9))/(1 - x^2 - 3 x^3 - 4 x^4 - 4 x^5 - x^6 - 2 x^7 - 3 x^8 - 5 x^9 - 4 x^10 - 2 x^11), {x, 0, 20}], x] (* Eric W. Weisstein, Aug 04 2017 *)
  • PARI
    Vec((1+x)*(2+4*x+x^2+5*x^3+x^4+3*x^5+5*x^6+3*x^7+2*x^8+2*x^9)/(1-x^2-3*x^3-4*x^4-4*x^5-x^6-2*x^7-3*x^8-5*x^9-4*x^10-2*x^11)+O(x^40)) \\ Andrew Howroyd, Aug 01 2017
    

Formula

From Andrew Howroyd, Aug 01 2017: (Start)
a(n) = a(n-2) + 3*a(n-3) + 4*a(n-4) + 4*a(n-5) + a(n-6) + 2*a(n-7) + 3*a(n-8) + 5*a(n-9) + 4*a(n-10) + 2*a(n-11) for n > 11.
G.f.: x*(1+x)*(2 + 4*x + x^2 + 5*x^3 + x^4 + 3*x^5 + 5*x^6 + 3*x^7 + 2*x^8 + 2*x^9)/(1 - x^2 - 3*x^3 - 4*x^4 - 4*x^5 - x^6 - 2*x^7- 3*x^8 - 5*x^9 - 4*x^10 - 2*x^11).
(End)

Extensions

Terms a(9) and beyond from Andrew Howroyd, Aug 01 2017

A290382 Number of minimal dominating sets in the n X n grid graph.

Original entry on oeis.org

1, 6, 16, 306, 6958, 349178, 40307167, 8863408138, 4227470143437, 4108988275187691
Offset: 1

Views

Author

Eric W. Weisstein, Jul 28 2017

Keywords

Crossrefs

Main diagonal of A286847.
Cf. A133515 (dominating sets), A286869 (irredundant sets).

Extensions

a(5)-a(9) from Andrew Howroyd, Jul 31 2017
a(10) from Christian Sievers, Dec 03 2023

A350823 Array read by antidiagonals: T(m,n) is the domination number of the grid graph P_m X P_n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 2, 3, 3, 3, 2, 2, 3, 4, 4, 3, 2, 3, 4, 4, 4, 4, 4, 3, 3, 4, 5, 6, 6, 5, 4, 3, 3, 5, 6, 7, 7, 7, 6, 5, 3, 4, 5, 7, 7, 8, 8, 7, 7, 5, 4, 4, 6, 7, 8, 9, 10, 9, 8, 7, 6, 4, 4, 6, 8, 10, 11, 11, 11, 11, 10, 8, 6, 4
Offset: 1

Views

Author

Andrew Howroyd, Jan 17 2022

Keywords

Comments

Equivalently, the minimum number of X-pentominoes needed to cover an m X n grid.

Examples

			Table begins:
===================================
m\n | 1  2  3  4  5  6  7  8  9
----+------------------------------
  1 | 1  1  1  2  2  2  3  3  3 ...
  2 | 1  2  2  3  3  4  4  5  5 ...
  3 | 1  2  3  4  4  5  6  7  7 ...
  4 | 2  3  4  4  6  7  7  8 10 ...
  5 | 2  3  4  6  7  8  9 11 12 ...
  6 | 2  4  5  7  8 10 11 12 14 ...
  7 | 3  4  6  7  9 11 12 14 16 ...
  8 | 3  5  7  8 11 12 14 16 18 ...
  9 | 3  5  7 10 12 14 16 18 20 ...
  ...
		

Crossrefs

Row 4 is A193768.
Main diagonal is A104519.

Formula

T(m,n) = T(n,m).
T(1,n) = ceiling(n/3); T(2,n) = floor(n/2) + 1.

A286848 Number of minimal dominating sets in the grid graph P_3 X P_n.

Original entry on oeis.org

2, 7, 16, 53, 154, 436, 1268, 3660, 10610, 30744, 89079, 258251, 748420, 2169219, 6287336, 18222901, 52817261, 153084840, 443698814, 1286012537, 3727362387, 10803344089, 31312289784, 90755170545, 263043739916, 762402920030, 2209739758798, 6404684091893
Offset: 1

Views

Author

Andrew Howroyd, Aug 01 2017

Keywords

Crossrefs

Row 3 of A286847.

Formula

G.f.: x*(2 + 3*x - 2*x^2 - x^3 + 4*x^4 + 10*x^5 - 14*x^6 - 32*x^7 - 29*x^8 - 2*x^9 - 21*x^10 - 140*x^11 - 140*x^12 + 126*x^13 + 80*x^14 + 127*x^15 + 143*x^16 + 695*x^17 + 401*x^18 + 462*x^19 + 582*x^20 - 8*x^21 - 490*x^22 - 660*x^23 - 721*x^24 - 960*x^25 - 714*x^26 - 925*x^27 + 25*x^28 + 206*x^29 + 255*x^30 + 494*x^31 + 155*x^32 + 443*x^33 - 118*x^34 + 80*x^35 - 71*x^36 - 172*x^37 + 78*x^38 - 105*x^39 + 79*x^40 + 7*x^41 - 28*x^42 + 33*x^43 - 7*x^44 - 4*x^45 + 3*x^46 - x^47) / (1 - 2*x - 2*x^2 - 4*x^3 + 8*x^4 - 2*x^5 - 2*x^6 - 23*x^7 + 14*x^8 + 31*x^9 + 31*x^10 - 45*x^11 + 50*x^12 + 83*x^13 + 122*x^14 - 141*x^15 - 54*x^16 - 105*x^17 + 36*x^18 - 85*x^19 - 275*x^20 - 222*x^21 + 63*x^22 + 90*x^23 - 140*x^24 + 253*x^25 + 399*x^26 + 234*x^27 + 190*x^28 - 87*x^29 + 59*x^30 - 219*x^31 - 222*x^32 - 189*x^33 - 270*x^34 + 152*x^35 + 56*x^36 + 123*x^37 + 158*x^38 - 41*x^39 + 75*x^40 - 62*x^41 - 12*x^42 + 21*x^43 - 30*x^44 + 7*x^45 + 4*x^46 - 3*x^47 + x^48) (conjectured). - Colin Barker, Aug 02 2017
a(n) = Sum_{k=1..48} c(k)*a(n-k), where c = (2, 2, 4, -8, 2, 2, 23, -14, -31, -31, 45, -50, -83, -122, 141, 54, 105, -36, 85, 275, 222, -63, -90, 140, -253, -399, -234, -190, 87, -59, 219, 222, 189, 270, -152, -56, -123, -158, 41, -75, 62, 12, -21, 30, -7, -4, 3, -1) (conjectured). - Eric W. Weisstein, Aug 02 2017

A291439 Array read by antidiagonals: T(m,n) = number of maximal irredundant sets in the grid graph P_m X P_n.

Original entry on oeis.org

1, 2, 2, 2, 6, 2, 4, 9, 9, 4, 6, 18, 32, 18, 6, 8, 54, 103, 103, 54, 8, 13, 99, 383, 590, 383, 99, 13, 17, 216, 1280, 2807, 2807, 1280, 216, 17, 27, 512, 4247, 13138, 21555, 13138, 4247, 512, 27, 40, 1079, 14354, 67564, 150063, 150063, 67564, 14354, 1079, 40
Offset: 1

Views

Author

Andrew Howroyd, Aug 23 2017

Keywords

Examples

			Array begins:
=================================================
m\n|  1   2    3     4       5       6       7
---|---------------------------------------------
1  |  1   2    2     4       6       8      13...
2  |  2   6    9    18      54      99     216...
3  |  2   9   32   103     383    1280    4247...
4  |  4  18  103   590    2807   13138   67564...
5  |  6  54  383  2807   21555  150063 1122252...
6  |  8  99 1280 13138  150063 1598353
7  | 13 216 4247 67564 1122252
...
		

Crossrefs

Rows 1-2 are A291055, A291100.
Main diagonal is A290790.
Showing 1-8 of 8 results.