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 1-7 of 7 results.

A234931 Number of tilings of a 5 X n rectangle using n pentominoes of shapes F, U, N.

Original entry on oeis.org

1, 0, 0, 0, 2, 0, 0, 0, 4, 0, 8, 0, 16, 0, 40, 0, 64, 16, 200, 96, 504, 464, 1528, 1664, 4376, 5616, 12792, 18192, 38264, 58384, 115832, 186368, 355808, 589344, 1095408, 1853664, 3383656, 5802016, 10470376, 18125280, 32461312, 56552736, 100782696, 176318464
Offset: 0

Views

Author

Alois P. Heinz, Jan 01 2014

Keywords

Examples

			a(4) = 2:
._______.   ._______.
| | ._. |   | ._. | |
| |_| |_|   |_| |_| |
|_. |_. |   | ._| ._|
| |_| | |   | | |_| |
|_____|_|   |_|_____|.
		

Crossrefs

Formula

G.f.: (4*x^20 +4*x^18 +8*x^16 -3*x^14 +4*x^13 -5*x^12 -2*x^11 +3*x^10 -2*x^9 +6*x^8 -2*x^7 +2*x^6 -2*x^5 -x^4 +2*x -1) / (-8*x^22 -28*x^20 -6*x^18 +8*x^17 +26*x^16 +4*x^15 +7*x^14 -8*x^13 -9*x^12 -14*x^11 +7*x^10 +2*x^9 +8*x^8 -2*x^7 +2*x^6 -6*x^5 +x^4 +2*x -1).

A247443 Number of tilings of a 5 X n rectangle using n pentominoes of shapes F, L, Y.

Original entry on oeis.org

1, 0, 2, 0, 6, 16, 32, 104, 186, 800, 1700, 4836, 11186, 29940, 84388, 208808, 563364, 1391664, 3787510, 9824684, 25712276, 66815444, 173151378, 457266220, 1188536784, 3113743272, 8087358736, 21152284376, 55283003950, 144314582896, 376852311434, 982507243820
Offset: 0

Views

Author

Alois P. Heinz, Sep 23 2014

Keywords

Examples

			a(5) = 16:
._._______.        ._______._.
| | ._____|        |_. .___| |
| |_| ._| |        | |_| ._| |
| |_. |_. |        | |_. |_. |
|___|_| | |        | ._|_| |_|
|_______|_| (*8)   |_|_______| (*8)  .
		

Crossrefs

Programs

  • Maple
    # Maple program: see link.

Formula

G.f.: see link.

A249762 Number of tilings of a 5 X n rectangle using n pentominoes of shapes F, I, L.

Original entry on oeis.org

1, 1, 3, 5, 13, 50, 133, 360, 875, 2254, 6336, 17331, 47199, 124476, 330344, 889454, 2400961, 6485476, 17392906, 46616158, 125153478, 336529923, 905611165, 2434088873, 6539233985, 17567977887, 47214493386, 126927551197, 341177175540, 916960655233
Offset: 0

Views

Author

Alois P. Heinz, Dec 03 2014

Keywords

Examples

			a(4) = 13:
._______.     ._______.     ._______.
| | | | |     | ._| ._|     | | ._| |
| | | | |     | |_. | |     | | | | |
| | | | |     | | |_| |     | | | | |
| | | | |     |_| ._| |     | |_| | |
|_|_|_|_| (1) |___|___| (2) |_|___|_| (2)
._______.     ._______.     ._______.
| ._| | |     | ._| ._|     | ._|_. |
| | | | |     | | | | |     | | | | |
| | | | |     | | | | |     | | | | |
|_| | | |     |_| |_| |     |_| | |_|
|___|_|_| (4) |___|___| (2) |___|___| (2) .
		

Crossrefs

Formula

a(n) ~ c * d^n, where d = 2.6877447474867836174937272605197376719631593933016281800670782370745298422..., c = 0.3236150736074998563483897952085529328299218049725560430481595704054051228... (1/d is the root of the denominator, see g.f.). - Vaclav Kotesovec, May 19 2015

A251617 Number of tilings of a 5 X n rectangle using n pentominoes of shapes F, I, L, U.

Original entry on oeis.org

1, 1, 3, 5, 19, 74, 219, 628, 1749, 5486, 17448, 53383, 160169, 479908, 1468366, 4512092, 13782535, 41855766, 127112554, 387469920, 1182800866, 3606789463, 10983721059, 33445214911, 101911804705, 310658892951, 946813182854, 2884825285301, 8789233684468
Offset: 0

Views

Author

Alois P. Heinz, Dec 05 2014

Keywords

Examples

			a(4) = 19 = 13 + 4 + 2 = A249762(4) + 4 + 2:
._______.     ._______.
|_____. |     | ._____|
| | ._|_|     |_| ._. |
| | |_. |     | |_| |_|
| |___| |     |_____| |
|___|___| (4) |_______| (2) .
		

Crossrefs

A251737 Number of tilings of a 5 X n rectangle using n pentominoes of shapes L, U, I.

Original entry on oeis.org

1, 1, 3, 5, 17, 66, 181, 508, 1283, 3664, 10812, 31171, 88565, 245524, 692416, 1968532, 5609977, 15928174, 44982196, 127190716, 360208608, 1021611491, 2896270245, 8202605953, 23226285083, 65780006703, 186369631872, 528047092459, 1495905404102, 4237308534243
Offset: 0

Views

Author

Alois P. Heinz, Dec 07 2014

Keywords

Examples

			a(4) = 17:
._______.     ._______.     ._______.     ._______.
|_____. |     | ._____|     | | | | |     | | ._| |
| | ._|_|     |_| ._. |     | | | | |     | | | | |
| | |_. |     | |_| |_|     | | | | |     | | | | |
| |___| |     |_____| |     | | | | |     | |_| | |
|___|___| (4) |_______| (2) |_|_|_|_| (1) |_|___|_| (2)
._______.     ._______.     ._______.
| ._| | |     | ._| ._|     | ._|_. |
| | | | |     | | | | |     | | | | |
| | | | |     | | | | |     | | | | |
|_| | | |     |_| |_| |     |_| | |_|
|___|_|_| (4) |___|___| (2) |___|___| (2) .
		

Crossrefs

A257866 Number of tilings of a 5 X n rectangle using n pentominoes of shapes W, I, L.

Original entry on oeis.org

1, 1, 3, 5, 19, 74, 209, 572, 1479, 4304, 13002, 38315, 109651, 308982, 884120, 2560952, 7428183, 21413028, 61433280, 176415916, 507985116, 1464725431, 4220293147, 12145885239, 34945690653, 100586823613, 289649303130, 834087280681, 2401368817168, 6912685066843
Offset: 0

Views

Author

Alois P. Heinz, May 11 2015

Keywords

Examples

			a(3) = 5:
._____. ._____. ._____. ._____. ._____.
| | | | | |_. | | ._| | | | ._| |_. | |
| | | | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | | | | |
| | | | | | |_| |_| | | | |_| | | |_| |
|_|_|_| |_|___| |___|_| |_|___| |___|_|.
a(4) = 19:
._______. ._______.
|_. |_. | | | ._| |
| |_. | | | | | | |
|_. |_| | | | | | |
| |___|_| | |_| | |
|_______| |_|___|_| ... .
		

Crossrefs

Formula

a(n) ~ c * d^n, where d = 2.878962978866730659679600165158895088546680936475540731494833253735549346144..., c = 0.33249894796240209167801000207088312509480543003269025485052861968247997... (1/d is the root of the denominator, see g.f.). - Vaclav Kotesovec, May 19 2015

A248102 Number of tilings of a 5 X 2n rectangle using 2n pentominoes of shapes N, Y.

Original entry on oeis.org

1, 0, 0, 18, 24, 238, 842, 4360, 25900, 112178, 613140, 2941170, 14789274, 74895336, 369603312, 1866863986, 9294391952, 46543456838, 233028690018, 1164275409976, 5830080180396, 29149585256266, 145845002931724, 729627382873090, 3649578988919810
Offset: 0

Views

Author

Alois P. Heinz, Oct 01 2014

Keywords

Examples

			a(3) = 18:
._______._._.        .___._______.        .___._______.
|_. .___| | |        |_. |___. ._|        |_. |___. ._|
| |_| | ._| |        | |_____|_| |        | |_____|_| |
| ._| | |_. |        | |___. ._| |        | |___. |_. |
| | ._|_| |_|        | ._| |_|_. |        | ._| |___| |
|_|_|_______| (*2)   |_|_______|_| (*8)   |_|_______|_| (*8)  .
		

Crossrefs

Formula

G.f.: (8*x^15 -52*x^14 -64*x^13 +1087*x^12 -2822*x^11 +2369*x^10 +810*x^9 -2047*x^8 +300*x^7 +122*x^6 +208*x^5 +x^4 +6*x^3 +9*x^2 +2*x -1) / (24*x^15 +4*x^14 -680*x^13 +2673*x^12 -4212*x^11 +2139*x^10 +1574*x^9 -2141*x^8 +456*x^7 -160*x^6 +236*x^5 -11*x^4 +24*x^3 +9*x^2 +2*x -1).
Showing 1-7 of 7 results.