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.

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A247712 Number T(n,k) of tilings of a 5 X n rectangle with pentominoes of any shape and exactly k pentominoes of shape Y; triangle T(n,k), n>=0, read by rows.

Original entry on oeis.org

1, 1, 5, 44, 12, 321, 136, 44, 2404, 1160, 404, 24, 14, 14692, 9380, 3388, 392, 90, 8, 98831, 78492, 30834, 5724, 748, 60, 684729, 631020, 292250, 74016, 13280, 1428, 58, 4642752, 4944856, 2628566, 788284, 171368, 25648, 3648, 228, 4
Offset: 0

Views

Author

Alois P. Heinz, Sep 23 2014

Keywords

Comments

Sum_{k>0} k * T(n,k) = A247745(n).
T(10*n,10*n) = 10^n = A011557(n).

Examples

			T(3,1) = 12:
._____.        ._____.        ._____.
| |_. |        |_.   |        | |_. |
| ._| |        | |___|        | ._| |
| | | |        | ._| |        | |___|
|_| |_|        | |   |        |_|   |
|_____| (*4)   |_|___| (*4)   |_____| (*4)  .
T(10,10) = 10:
.___________________.
|_. .___| |___. ._| |
| |_| |_______|_|_. |
| |_______|___. ._| |
| ._| |___. ._|_| |_|
|_|_______|_|_______| ... .
Triangle T(n,k) begins:
00 :      1;
01 :      1;
02 :      5;
03 :     44,     12;
04 :    321,    136,     44;
05 :   2404,   1160,    404,    24,    14;
06 :  14692,   9380,   3388,   392,    90,    8;
07 :  98831,  78492,  30834,  5724,   748,   60;
08 : 684729, 631020, 292250, 74016, 13280, 1428, 58;
		

Crossrefs

Row sums give A174249 or A233427(n,5).
Column k=0 gives A247776.

A247713 Number T(n,k) of tilings of a 5 X n rectangle with pentominoes of any shape and exactly k pentominoes of shape Z; triangle T(n,k), n>=0, read by rows.

Original entry on oeis.org

1, 1, 5, 52, 4, 451, 48, 2, 3498, 484, 24, 23502, 4136, 300, 12, 173611, 37674, 3262, 142, 1323447, 335388, 35938, 1964, 44, 9920654, 2892492, 365458, 25752, 986, 12, 73573634, 24266128, 3544842, 298200, 15002, 400, 6, 545170514, 200531918, 33123244, 3236018, 198380, 7546, 164, 2
Offset: 0

Views

Author

Alois P. Heinz, Sep 23 2014

Keywords

Comments

Sum_{k>0} k * T(n,k) = A247746(n).

Examples

			T(3,1) = 4:
._____.        ._____.
|___. |        |   ._|
|_. | |        |___| |
| | |_|        | .___|
| |___|        |_|   |
|_____| (*2)   |_____| (*2)  .
Triangle T(n,k) begins:
00 :        1;
01 :        1;
02 :        5;
03 :       52,        4;
04 :      451,       48,       2;
05 :     3498,      484,      24;
06 :    23502,     4136,     300,     12;
07 :   173611,    37674,    3262,    142;
08 :  1323447,   335388,   35938,   1964,    44;
09 :  9920654,  2892492,  365458,  25752,   986,  12;
10 : 73573634, 24266128, 3544842, 298200, 15002, 400, 6;
		

Crossrefs

Row sums give A174249 or A233427(n,5).
Column k=0 gives A247777.
Cf. A247746.

A264765 Number of tilings of a 5 X n rectangle using n pentominoes of shapes Z, I, P.

Original entry on oeis.org

1, 1, 3, 7, 17, 78, 195, 616, 1783, 5120, 16714, 48843, 150407, 453178, 1356478, 4174538, 12554221, 38233788, 115868736, 350343710, 1065875246, 3225913135, 9793613873, 29699991965, 90011535049, 273180669975, 828073217940, 2511974932751, 7618229843186
Offset: 0

Views

Author

Alois P. Heinz, Nov 23 2015

Keywords

Examples

			a(3) = 7:
._____.  ._____.  ._____.  ._____.  ._____.  ._____.  ._____.
| | | |  | |   |  | |   |  |   | |  |   | |  |_.   |  |   ._|
| | | |  | | ._|  | |_. |  | ._| |  |_. | |  | |___|  |___| |
| | | |  | |_| |  | | |_|  |_| | |  | |_| |  |___. |  | .___|
| | | |  | |   |  | |   |  |   | |  |   | |  |   |_|  |_|   |
|_|_|_|  |_|___|  |_|___|  |___|_|  |___|_|  |_____|  |_____|  .
		

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).

A247117 Number of tilings of a 10 X n rectangle using 2n pentominoes of shape I.

Original entry on oeis.org

1, 1, 1, 1, 1, 8, 17, 28, 41, 56, 144, 317, 609, 1060, 1716, 3324, 6713, 13188, 24624, 43620, 80464, 153645, 296025, 562097, 1037921, 1920661, 3600832, 6820873, 12920804, 24211457, 45173688, 84493668, 158848825, 299451277, 562923960, 1055117520, 1976475968
Offset: 0

Views

Author

Alois P. Heinz, Nov 19 2014

Keywords

Crossrefs

Cf. A174249, A233427, A003520 (5 X n), A247218 (15 X n).
Column k=5 of A250662.

Programs

  • Maple
    gf:= -(x^10+x^8-x^6-2*x^5-x^4-x^3+1) *(x-1)^4 *(x^4+x^3+x^2+x+1)^4 / (x^35 +x^33 -2*x^31 -7*x^30 -2*x^29 -6*x^28 +x^27 +9*x^26 +22*x^25 +8*x^24 +15*x^23 -4*x^22 -15*x^21 -39*x^20 -12*x^19 -20*x^18 +6*x^17 +10*x^16 +45*x^15 +8*x^14 +19*x^13 -4*x^12 -4*x^11 -33*x^10 -6*x^9 -10*x^8 +x^7 -3*x^6 +12*x^5 +x^3 +x-1):
    a:= n-> coeff(series(gf, x, n+1), x, n):
    seq(a(n), n=0..50);

Formula

G.f.: see Maple program.

A247126 Number of tilings of a 5 X n rectangle using n pentominoes of shapes F, U, X, N.

Original entry on oeis.org

1, 0, 0, 1, 2, 0, 1, 4, 4, 1, 14, 12, 17, 32, 64, 81, 138, 272, 489, 764, 1548, 2809, 5062, 9420, 17721, 32712, 60992, 114105, 213890, 398784, 747745, 1401476, 2624004, 4916369, 9218118, 17274340, 32378521, 60694768, 113785984, 213293721, 399856922, 749628208
Offset: 0

Views

Author

Alois P. Heinz, Nov 19 2014

Keywords

Crossrefs

Programs

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

Formula

G.f.: see Maple program.

A349187 Number of tilings of a 5 X n rectangle using n pentominoes of shapes X, Y, Z.

Original entry on oeis.org

1, 0, 0, 0, 0, 6, 6, 6, 2, 10, 86, 118, 166, 152, 372, 1394, 2450, 3866, 4946, 10160, 26380, 50770, 86522, 131632, 251150, 548436, 1075036, 1918294, 3205242, 5953962, 11962044, 23255472, 42565706, 74859582, 138078796, 266506794, 511327170, 947685504, 1713749022
Offset: 0

Views

Author

Alois P. Heinz, Nov 09 2021

Keywords

Examples

			a(5) = 6:
  ._________.     ._________.
  |_. ._._| |     | |___. ._|
  | |_| |_. |     | |_  |_| |
  | |_. ._| |     | ._| |_. |
  | ._|_| |_| (2) |_| |___| | (4)
  |_|_______|     |_______|_|      .
.
a(8) = 2:
  ._______________.
  |_. | |___. ._| |
  | | |___. |_|_. |
  | |___| |_|_. | |
  | ._| |___. | |_| (2)
  |_|_______|_|___|      .
.
		

Crossrefs

Formula

G.f.: (x^20 +6*x^19 +5*x^18 +7*x^15 +14*x^14 +7*x^13 +4*x^10 +2*x^9 +x^8 -2*x^7 -x^6 -7*x^5 -3*x^4 +1) / (11*x^20 +16*x^19 +5*x^18 +2*x^16 +33*x^15 +38*x^14 +7*x^13 +8*x^12 +20*x^11 +14*x^10 +10*x^9 -x^8 -8*x^7 -7*x^6 -13*x^5 -3*x^4 +1).

A247076 Number of tilings of a 5 X 2n rectangle using 2n pentominoes of shape P.

Original entry on oeis.org

1, 2, 6, 20, 62, 194, 612, 1922, 6038, 18980, 59646, 187442, 589076, 1851266, 5817894, 18283700, 57459518, 180575906, 567489348, 1783428098, 5604714422, 17613731780, 55354032894, 173959101458, 546694927604, 1718078222594, 5399341807686, 16968314698580
Offset: 0

Views

Author

Alois P. Heinz, Nov 17 2014

Keywords

Examples

			a(2) = 6:
._______. ._______. ._______. ._______. ._______. ._______.
|   |   | |   |   | |   |   | |   |   | |   ._| | | |_.   |
| ._| ._| |_. |_. | | ._|_. | |_. | ._| |___|   | |   |___|
|_| |_| | | |_| |_| |_| | |_| | |_|_| | |   |___| |___|   |
|   |   | |   |   | |   |   | |   |   | | ._|   | |   |_. |
|___|___| |___|___| |___|___| |___|___| |_|_____| |_____|_| .
		

Crossrefs

Even bisection of main diagonal of A247706.

Programs

  • Maple
    a:= proc(n) option remember; `if`(n<4, [1, 2, 6, 20][n+1],
           2*a(n-1) +2*a(n-2) +5*a(n-3))
        end:
    seq(a(n), n=0..40);
  • Mathematica
    Join[{1}, LinearRecurrence[{2, 2, 5}, {2, 6, 20}, 40]] (* Jean-François Alcover, May 29 2018 *)

Formula

G.f.: (x-1)*(x^2+x+1)/(5*x^3+2*x^2+2*x-1).
a(n) = 2*a(n-1)+2*a(n-2)+5*a(n-3) for n>3, a(0)=1; a(1)=2, a(2)=6, a(3)=20.

A247103 Number of tilings of a 5 X n rectangle using n pentominoes of shapes I, N, P, U, T.

Original entry on oeis.org

1, 1, 3, 11, 33, 166, 589, 2216, 8935, 33984, 137056, 539085, 2100341, 8324716, 32607928, 128652672, 507032667, 1992083368, 7853132654, 30894420646, 121642017784, 479048967517, 1885229164497, 7423732617043, 29223734864421, 115048209160729, 452968829090506
Offset: 0

Views

Author

Alois P. Heinz, Nov 20 2014

Keywords

Examples

			a(3) = 11:
._____.     ._____.     ._____.     ._____.
| | | |     |   | |     | |   |     |_.   |
| | | |     | ._| |     | | ._|     | |___|
| | | |     |_| ._|     | |_| |     | .___|
| | | |     | |_| |     | |   |     |_|   |
|_|_|_| (1) |_____| (4) |_|___| (4) |_____| (2) .
		

Crossrefs

A247196 Number of tilings of a 5 X n rectangle using n pentominoes of shapes T, I, P.

Original entry on oeis.org

1, 1, 3, 7, 17, 78, 199, 638, 1865, 5332, 17250, 50877, 156787, 475348, 1423432, 4367178, 13182353, 40122074, 121916294, 369052634, 1122475534, 3403574961, 10335095973, 31385295907, 95218937465, 289154182737, 877572289140, 2663965244527, 8087517963748
Offset: 0

Views

Author

Alois P. Heinz, Nov 24 2014

Keywords

Examples

			a(3) = 7:
._____. ._____. ._____. ._____. ._____. ._____. ._____.
|_.   | | |   | | | | | | |   | |   | | |   | | |   ._|
| |___| | | ._| | | | | | |_. | |_. | | | ._| | |___| |
| .___| | |_| | | | | | | | |_| | |_| | |_| | | |___. |
|_|   | | |   | | | | | | |   | |   | | |   | | |   |_|
|_____| |_|___| |_|_|_| |_|___| |___|_| |___|_| |_____| .
		

Crossrefs

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