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 1-5 of 5 results.

A264812 Number of tilings of a 5 X n rectangle using n pentominoes of shapes P, I, X.

Original entry on oeis.org

1, 1, 3, 5, 13, 52, 123, 366, 909, 2444, 7108, 19157, 53957, 146826, 400704, 1115852, 3059907, 8475420, 23369304, 64225984, 177572352, 488839323, 1349102071, 3722419367, 10255126169, 28303059509, 78013005366, 215160477217, 593488173404, 1636220978049
Offset: 0

Views

Author

Alois P. Heinz, Nov 25 2015

Keywords

Examples

			a(4) = 13:
._______.      ._______.      ._______.      ._______.
| | | | |      |   |   |      |   | | |      |   ._| |
| | | | |      | ._| ._|      | ._| | |      |___|   |
| | | | |      |_| |_| |      |_| | | |      |   |___|
| | | | | (1)  |   |   | (4)  |   | | | (6)  | ._|   | (2)
|_|_|_|_|      |___|___|      |_ _|_|_|      |_|_____|    .
a(5) = 52:
._________.
|   |_.   |
| ._| |___|
|_|_   _| |
|   |_|   | (2)  ...
|_____|___|          .
		

Crossrefs

A343529 Number of tilings of a 5 X n rectangle using n pentominoes of shapes P, X, Y.

Original entry on oeis.org

1, 0, 2, 4, 18, 36, 138, 334, 1066, 3096, 9490, 26826, 80468, 235718, 699056, 2055466, 6074498, 17857906, 52725190, 155445504, 458505084, 1351257730, 3984941402, 11748306100, 34643781158, 102144907886, 301179533022, 887996181502, 2618324249106, 7720149428450
Offset: 0

Views

Author

Alois P. Heinz, Apr 18 2021

Keywords

Examples

			a(2) = 2,        a(3) = 4:     a(5) = 36:
  .___.  .___.     ._____.       ._________.     ._________.
  |   |  |   |     |_.   |       |   |_.   |     |_. ._._| |
  | ._|  |_. |     | |___|       | ._| |___|     | |_| |_. |
  |_| |  | |_|     | ._| |       |_|_. ._| |     | |_. ._| |
  |   |  |   |     | |   | (4)   |   |_|   | (2) | ._|_| |_| (2)  ...
  |___|  |___|     |_|___|       |_____|___|     |_|_______|          .
.
a(4) = 18:
  .___.___.     .___.___.     ._._____.     ._______.
  |   |   |     |   |   |     | |_.   |     |___. ._|
  | ._|_. |     | ._| ._|     |   |___|     |   |_| |
  |_| | |_|     |_| |_| |     |___|   |     | ._|   |
  |   |   | (2) |   |   | (2) |   |_. | (2) |_| |___| (2)
  |___|___|     |___|___|     |_____|_|     |_______|
.
  ._______.     ._._____.     ._______.
  | |   ._|     | |_.   |     |___. ._|
  | |___| |     | ._|___|     |   |_| |
  | ._|_. |     | |_.   |     | ._|_. |
  |_|   | | (2) |_| |___| (4) |_|   | | (4)
  |_____|_|     |_______|     |_____|_|     .
		

Crossrefs

Formula

G.f.: (16*x^54 +32*x^53 -128*x^51 -80*x^50 +380*x^49 +540*x^48 +456*x^47 -1316*x^46 -28*x^45 +976*x^44 +6016*x^43 +3356*x^42 -1680*x^41 -5992*x^40 -919*x^39 -825*x^38 +5838*x^37 -12209*x^36 -14876*x^35 -17029*x^34 -15243*x^33 -13879*x^32 -8029*x^31 -17115*x^30 -3713*x^29 -6022*x^28 -110*x^27 +1321*x^26 -832*x^25 -212*x^24 +4478*x^23 -575*x^22 -808*x^21 -3929*x^20 -574*x^19 +314*x^18 -1001*x^17 -1354*x^16 -805*x^15 -493*x^14 -299*x^13 -229*x^12 -78*x^11 +177*x^10 -39*x^9 -50*x^8 -19*x^7 +13*x^6 +15*x^5 +6*x^4 +3*x^3 +2*x^2 -1) /
(144*x^54 +224*x^53 +224*x^52 -1024*x^51 -848*x^50 -2228*x^49 +5668*x^48 +4136*x^47 -11260*x^46 -13154*x^45 +8426*x^44 +34252*x^43 +24792*x^42 -56180*x^41 -47120*x^40 +7095*x^39 +61021*x^38 +36892*x^37 -48989*x^36 -41768*x^35 +68397*x^34 +7921*x^33 +9893*x^32 -30841*x^31 +15927*x^30 +54995*x^29 +5474*x^28 -24546*x^27 -1559*x^26 -11350*x^25 +6196*x^24 -2886*x^23 -761*x^22 -3634*x^21 -13769*x^20 -6060*x^19 +880*x^18 +1445*x^17 -702*x^16 -1515*x^15 -1843*x^14 -223*x^13 -511*x^12 +172*x^11 +399*x^10 -153*x^9 -198*x^8 -61*x^7 +19*x^6 +21*x^5 +16*x^4 +7*x^3 +4*x^2 -1).

A278964 Number of tilings of a 6 X n rectangle using pentominoes of shapes L, U, X and monominoes.

Original entry on oeis.org

1, 1, 31, 432, 9851, 150749, 2392788, 38885816, 646657365, 10599739324, 173226495187, 2835753730682, 46501906844608, 762113847626540, 12484929995911672, 204541850515528677, 3351522453919340317, 54915791725126323755, 899777273419073185968
Offset: 0

Views

Author

Alois P. Heinz, Dec 02 2016

Keywords

Examples

			a(2) = 31:
.___. .___. .___. .___. .___. .___. .___. .___. .___. .___. .___.
|_|_| | ._| | ._| |_|_| |_|_| |_|_| |_. | |_. | |_|_| |_|_| |_|_|
|_|_| | |_| | |_| | ._| |_|_| |_|_| |_| | |_| | |_. | |_|_| |_|_|
|_|_| |___| |___| | |_| | ._| |_|_| |___| |___| |_| | |_. | |_|_|
|_|_| | ._| |_|_| |___| | |_| | ._| |_. | |_|_| |___| |_| | |_. |
|_|_| | |_| |_|_| |_|_| |___| | |_| |_| | |_|_| |_|_| |___| |_| |
|_|_| |___| |_|_| |_|_| |_|_| |___| |___| |_|_| |_|_| |_|_| |___|
.___. .___. .___. .___. .___. .___. .___. .___. .___. .___. .___.
| ._| |_. | | |_| |_|_| |_|_| |_. | |_. | |_|_| |_. | |_|_| |_|_|
| |_| |_| | | |_| | |_| |_|_| | | | |_| | |_. | |_| | |_. | |_|_|
|___| |___| | |_| | |_| | |_| | | | | | | | | | |_| | |_| | |_. |
|_. | | ._| |___| | |_| | |_| | |_| | |_| | | | |_|_| |_| | |_| |
|_| | | |_| |_|_| |___| | |_| |___| | |_| | |_| |_|_| |_|_| |_| |
|___| |___| |_|_| |_|_| |___| |_|_| |___| |___| |_|_| |_|_| |_|_|
.___. .___. .___. .___. .___. .___. .___. .___. .___.
| ._| |_|_| |_|_| | ._| | ._| |_|_| |_|_| |_|_| |_| |
| |_| | ._| |_|_| | | | | |_| | ._| |_|_| |_| | |_| |
| |_| | |_| | ._| | | | | | | | | | |_| | |_| | |_| |
|_|_| | |_| | |_| |_| | |_| | | | | |_| | |_| | |___|
|_|_| |_|_| | |_| |___| |_| | |_| | |_| | |___| |_|_|
|_|_| |_|_| |_|_| |_|_| |___| |___| |___| |_|_| |_|_|  .
		

Crossrefs

A286347 Number of tilings of a 6 X n rectangle using pentominoes of shapes X, Y, T and monominoes.

Original entry on oeis.org

1, 1, 15, 188, 3763, 54368, 790504, 11771179, 176285795, 2627027061, 39172906410, 584774465361, 8725442013820, 130117410190768, 1940656499251689, 28950613608637003, 431889355175650435, 6442566792491842258, 96102610815876310611, 1433558139553752297236
Offset: 0

Views

Author

Alois P. Heinz, May 08 2017

Keywords

Crossrefs

A286391 Number of tilings of a 6 X n rectangle using pentominoes of shapes X, Y, Z, T and monominoes.

Original entry on oeis.org

1, 1, 15, 344, 6835, 119392, 2136080, 38329669, 688355077, 12374676591, 222673114420, 4005005917279, 72004800735036, 1294444641691072, 23273376392535695, 418470613768822683, 7524342117053834729, 135288703461639048592, 2432489164334993344213
Offset: 0

Views

Author

Alois P. Heinz, May 08 2017

Keywords

Examples

			a(2) = 15:
.___. .___. .___. .___. .___. .___. .___. .___. .___.
|_|_| | |_| |_| | | |_| |_|_| |_|_| |_|_| |_|_| | |_|
|_|_| | ._| |_. | | ._| | |_| |_|_| |_|_| | |_| | |_|
|_|_| | | | | | | | |_| | ._| | |_| | |_| | |_| | ._|
|_|_| |_| | | |_| |_|_| | |_| | ._| | |_| | ._| |_|_|
|_|_| |_. | | ._| |_|_| |_|_| | |_| | ._| |_|_| |_|_|
|_|_| |_|_| |_|_| |_|_| |_|_| |_|_| |_|_| |_|_| |_|_|
.___. .___. .___. .___. .___. .___.
|_| | |_|_| |_|_| |_|_| |_|_| |_| |
|_. | |_| | |_|_| |_|_| |_| | |_| |
|_| | |_. | |_| | |_| | |_| | |_. |
|_|_| |_| | |_. | |_| | |_. | |_|_|
|_|_| |_|_| |_| | |_. | |_|_| |_|_|
|_|_| |_|_| |_|_| |_|_| |_|_| |_|_|  .
		

Crossrefs

Showing 1-5 of 5 results.