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.

Previous Showing 41-50 of 81 results. Next

A247218 Number of tilings of a 15 X n rectangle using 3n pentominoes of shape I.

Original entry on oeis.org

1, 1, 1, 1, 1, 34, 95, 190, 325, 506, 3324, 10353, 25607, 55346, 108756, 389216, 1208901, 3281686, 8006108, 17950204, 51430928, 150609259, 419540401, 1090827453, 2651884943, 7077981621, 19691707908, 54499735145, 145671654672, 371632691473, 976543067070
Offset: 0

Views

Author

Alois P. Heinz, Nov 26 2014

Keywords

Crossrefs

Column k=5 of A251072.

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

A352421 Number of tilings of a 5 X n rectangle using n pentominoes of shapes U, Y, Z.

Original entry on oeis.org

1, 0, 0, 0, 0, 4, 6, 8, 6, 8, 54, 112, 182, 232, 404, 930, 2054, 3880, 6304, 10696, 20696, 42396, 81554, 146240, 259534, 480084, 924860, 1768856, 3284468, 5992798, 11044774, 20756310, 39209398, 73369392, 135855648, 251495794, 468915328, 878762056, 1644145874
Offset: 0

Views

Author

Alois P. Heinz, Apr 25 2022

Keywords

Examples

			a(7) = 8:
  ._____________.     ._____________.     ._____________.
  |_. .___| | ._|     |_. .___| ._| |     | |_. .___| ._|
  | |_| .___| | |     | |_|_. | |_. |     | ._|_| ._| | |
  | ._|_| |___| |     | |_. | |___| |     | | ._| |___| |
  | | .___| |_. | (4) | ._| |___| |_| (2) |_| |___| |_. | (2)
  |_|_|_______|_|     |_|___|_______|     |___|_______|_|      .
.
		

Crossrefs

Formula

G.f.: (16*x^42 -16*x^41 +3*x^40 -20*x^39 -28*x^38 +28*x^37 -2*x^36 +31*x^35 +15*x^34 -38*x^33 -29*x^32 +9*x^31 +20*x^30 +69*x^29 +3*x^28 -10*x^27 +10*x^26 +2*x^25 +31*x^24 -10*x^23 -20*x^22 -41*x^21 -37*x^20 -25*x^19 +7*x^18 +8*x^17 -3*x^16 -28*x^15 -31*x^14 -9*x^13 +x^12 +2*x^11 +7*x^10 +6*x^9 -2*x^8 +4*x^7 +2*x^6 +4*x^5 +3*x^4 -1) / (2*x^45 +24*x^42 -44*x^41 -29*x^40 -42*x^39 +30*x^38 +64*x^37 +84*x^36 +79*x^35 -3*x^34 -96*x^33 -79*x^32 +61*x^31 +70*x^30 +67*x^29 -53*x^28 +82*x^26 +44*x^25 -67*x^24 -128*x^23 -110*x^22 -71*x^21 -73*x^20 -13*x^19 +39*x^18 -20*x^17 -65*x^16 -90*x^15 -29*x^14 -x^13 +5*x^12 +10*x^11 +11*x^10 +2*x^9 +4*x^8 +12*x^7 +8*x^6 +8*x^5 +3*x^4 -1).

A361250 Number of tilings of a 5 X n rectangle using n pentominoes of shapes T, N, X.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 2, 2, 8, 0, 18, 6, 16, 6, 48, 22, 74, 48, 182, 74, 306, 204, 544, 342, 1114, 826, 2038, 1546, 4144, 3126, 7452, 6470, 14538, 12542, 27824, 25994, 53398, 50244, 103288, 101306, 195756, 200120, 380310, 395802
Offset: 0

Views

Author

Alois P. Heinz, Apr 20 2023

Keywords

Examples

			a(10) = 2:
   .___________________.
   |___. |_. ._| .___| |
   |_. |___| |___|___  |
   | |_____|_| |___. |_|
   | .___| ._| |_. |___|
   |_|_____|_____|_____|  ... and its mirror.
.
a(14) = 2:
   .___________________________.
   |___. |_. ._| |_. ._| .___| |
   |_. |___| |_. ._| |___|___  |
   | |_____|_| |_| |_| |___. |_|
   | .___| ._| |_. ._| |_. |___|
   |_|_____|_____|_|_____|_____|  ... and its mirror.
.
a(16) = 2:
   ._______________________________.
   |___. |_. ._| .___|_. ._| .___| |
   |_. |___| |___| .___| |___|___  |
   | |_____|_| |___| ._|_| |___. |_|
   | .___| ._| |_____| ._| |_. |___|
   |_|_____|_____|_____|_____|_____|  ... and its mirror.
.
a(17) = 2:
   ._________________________________.
   |___. |_. ._| |___. |_. ._| .___| |
   |_. |___| |_. ._| |___| |___|___  |
   | |_____|_| |_|_. ._| |_| |___. |_|
   | .___| ._| |_. |_|_. ._| |_. |___|
   |_|_____|_____|_____|_|_____|_____|  ... and its mirror.
.
		

Crossrefs

Programs

  • Maple
    gf:= (x^14+4*x^13+2*x^11-4*x^10+x^9-3*x^8-x^6-x^4-x^3+1)/
         (x^14+6*x^13+2*x^11-6*x^10+x^9-3*x^8-x^6-x^4-x^3+1):
    a:= n-> coeff(series(gf, x, n+1), x, n):
    seq(a(n), n=0..66);

A246764 Number of tilings of a 5 X n rectangle using n pentominoes of shapes P, I, N, T.

Original entry on oeis.org

1, 1, 3, 7, 17, 78, 247, 916, 3301, 11272, 41854, 150485, 538585, 1954912, 6978464, 25170446, 90851829, 326048198, 1176355862, 4230352602, 15222263126, 54855015353, 197302183497, 710556528403, 2557837610375, 9205575728179, 33148388282116, 119307072980025
Offset: 0

Views

Author

Alois P. Heinz, Nov 28 2014

Keywords

Crossrefs

A246902 Number of tilings of a 5 X n rectangle using n pentominoes of distinct shapes.

Original entry on oeis.org

1, 1, 0, 28, 200, 856, 2164, 5584, 13632, 23608, 27804, 16412, 4040
Offset: 0

Views

Author

Alois P. Heinz, Nov 16 2014

Keywords

Examples

			a(3) = 28: 4 orientations of each of the following 7 patterns:
  ._____. ._____. ._____. ._____. ._____. ._____. ._____.
  |___. | | |   | |_. ._| | .___| |   | | |_.   | | ._| |
  | | | | | | ._| | | | | | |   | | ._| | | |___| | |_. |
  | | |_| | |_| | | |_| | |_| ._| |_| ._| |_. ._| |___| |
  | |_. | |___| | | |_. | | |_| | | |_| | | |_| | |   |_|
  |___|_| |_____| |___|_| |_____| |_____| |_____| |_____| .
		

Crossrefs

A247121 Number of tilings of a 5 X 2n rectangle using 2n pentominoes of shapes P, U.

Original entry on oeis.org

1, 2, 12, 56, 248, 1184, 5472, 25376, 118208, 548864, 2550912, 11856896, 55098368, 256070144, 1190065152, 5530658816, 25703241728, 119453057024, 555145224192, 2579979739136, 11990182412288, 55723107221504, 258967268524032, 1203523043065856, 5593246378754048
Offset: 0

Views

Author

Alois P. Heinz, Nov 19 2014

Keywords

Examples

			a(2) = 12:
._______.      ._______.      ._______.      ._______.
|   |   |      |   ._| |      | ._|   |      | ._|   |
| ._| ._|      |___|   |      | |_____|      | |_____|
|_| |_| |      |   |___|      |___|   |      |___|_. |
|   |   |      | ._|   |      |   |_. |      |   ._| |
|___|___| (*4) |_|_____| (*2) |_____|_| (*4) |___|___| (*2) .
		

Crossrefs

Programs

  • Maple
    a:= n-> ceil((<<0|1|0>, <0|0|1>, <20|8|2>>^(n-1). <<2, 12, 56>>)[1, 1]):
    seq(a(n), n=0..30);

Formula

G.f.: (4*x^3-1)/(20*x^3+8*x^2+2*x-1).

A247127 Number of tilings of a 5 X n rectangle using n pentominoes of shapes V, U, X, N.

Original entry on oeis.org

1, 0, 0, 1, 4, 0, 9, 8, 24, 17, 78, 64, 227, 212, 664, 699, 2004, 2220, 6033, 7196, 18112, 22859, 54882, 72560, 166251, 229284, 505632, 721421, 1540532, 2264668, 4702135, 7092742, 14376450, 22165709, 44024116, 69154334, 134973515, 215459398, 414268932
Offset: 0

Views

Author

Alois P. Heinz, Nov 19 2014

Keywords

Crossrefs

Programs

  • Maple
    gf:= -(4*x^18 +4*x^17 -8*x^16 -3*x^15 -9*x^14 +2*x^13 -3*x^12 +5*x^11 -7*x^10 +x^9 -7*x^8 -x^6 -2*x^5 -x^3+1) / (32*x^26 +32*x^25 -32*x^24 +8*x^23 -120*x^22 +12*x^21 -124*x^20 +36*x^19 -123*x^18 +35*x^17 -106*x^16 +20*x^15 -62*x^14 -23*x^13 -22*x^12 -36*x^11 +5*x^10 -18*x^9 +13*x^8 -4*x^7 +8*x^6 +2*x^5 +4*x^4 +2*x^3-1):
    a:= n-> coeff(series(gf, x, n+1), x, n):
    seq(a(n), n=0..50);

Formula

G.f.: see Maple program.
Previous Showing 41-50 of 81 results. Next