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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A354011 Number of tilings of a 3 X n rectangle using 2 X 2 tiles, right trominoes and dominoes.

Original entry on oeis.org

1, 0, 7, 8, 81, 184, 1051, 3176, 14609, 50408, 210903, 773888, 3102369, 11711856, 46045259, 176114128, 686258465, 2640610128, 10247733223, 39540368248, 153162778865, 591718044968, 2290106238779, 8852558325048, 34248315785777, 132424316290104, 512224146701367
Offset: 0

Views

Author

Gerhard Kirchner, May 14 2022

Keywords

Comments

For tiling algorithm, see A351322.

Examples

			a(2)=7:
   ___    ___    ___    ___    ___    ___    ___
  |   |  |___|  |_  |  |  _|  |___|  |___|  |_|_|
  |___|  |   |  | |_|  |_| |  |___|  |_|_|  |_|_|
  |___|  |___|  |___|  |___|  |___|  |_|_|  |___|
		

Crossrefs

Programs

Formula

G.f.: (1 - 2*x - 2*x^2 + 2*x^3 - x^4) / (1 - 2*x - 9*x^2 + 8*x^3 - 3*x^4 - 6*x^5 + 3*x^6).
a(n)=2*a(n-1) + 9*a(n-2) - 8*a(n-3) + 3*a(n-4) + 6*a(n-5) - 3*a(n-6).

A354012 Number of tilings of a 4 X n rectangle using 2 X 2 tiles, right trominoes and dominoes.

Original entry on oeis.org

1, 1, 17, 81, 702, 4623, 35044, 248045, 1819731, 13110984, 95362462, 690253391, 5008926698, 36300216768, 263252448712, 1908449014617, 13837881924141, 100326715619679, 727420462629671, 5274035027493046, 38238994112367061, 277246970248002472, 2010151423463689959
Offset: 0

Views

Author

Gerhard Kirchner, May 14 2022

Keywords

Comments

For tiling algorithm, see A351322.

Examples

			a(2)=17, mirroring included (h: horizontal, v: vertical):
    v     v          h,v                      v           h
   ___   ___   ___   ___   ___   ___   ___   ___   ___   ___
  |   | |   | |   | |___| |___| | | | |___| |___| |___| |  _|
  |___| |___| |___| |_  | |___| |_|_| | | | |___| |   | |_| |
  |___| | | | |   | | |_| |___| | | | |_|_| | | | |___| | |_|
  |___| |_|_| |___| |___| |___| |_|_| |___| |_|_| |___| |___|
    2  +  2  +  1  +  4  +  1  +  1  +  1  +  2  +  1  +  2  = 17.
		

Crossrefs

Programs

Formula

G.f.: (1 - 4*x - 16*x^2 + 37*x^3 + 32*x^4 - 34*x^5 + 4*x^6 + 2*x^7 - 2*x^8) / (1 - 5*x - 28*x^2 + 69*x^3 + 142*x^4 - 194*x^5 - 78*x^6 + 57*x^7 + 36*x^8 - 70*x^9 + 32*x^10).
a(n)=5*a(n-1) + 28*a(n-2) - 69*a(n-3) - 142*a(n-4) + 194*a(n-5) + 78*a(n-6) - 57*a(n-7) - 36*a(n-8) + 70*a(n-9) - 32*a(n-10).

A354130 Triangle read by rows: T(k,n) (k >= 0, n = 0, ..., k) = number of tilings of a k X n rectangle using 2 X 2, and 1 X 1 tiles, right trominoes and dominoes.

Original entry on oeis.org

1, 1, 1, 1, 2, 12, 1, 3, 48, 405, 1, 5, 216, 4185, 103300, 1, 8, 936, 40320, 2352830, 124098498, 1, 13, 4104, 397755, 55004286, 6763987198, 863829618636, 1, 21, 17928, 3892293, 1274945897, 364713815832, 108969107997657, 32100965172272499
Offset: 0

Views

Author

Gerhard Kirchner, May 18 2022

Keywords

Comments

Tiling algorithm, see A351322.
Reading the sequence {T(k,n)} for n>k, use T(n,k) instead of T(k,n).
T(1,n) = A000045(n+1), Fibonacci numbers.
T(2,n) = A354131(n), T(3,n) = A354132(n).

Examples

			Triangle begins
k\n_0__1____2______3________4__________5____________6
0:  1
1:  1  1
2:  1  2   12
3:  1  3   48    405
4:  1  5  216   4185   103300
5:  1  8  936  40320  2352830  124098498
6:  1 13 4104 397755 55004286 6763987198 863829618636
		

Crossrefs

Programs

A354131 Number of tilings of a 2 X n rectangle using 2 X 2 and 1 X 1 tiles, right trominoes and dominoes.

Original entry on oeis.org

1, 2, 12, 48, 216, 936, 4104, 17928, 78408, 342792, 1498824, 6553224, 28652616, 125277192, 547747272, 2394904968, 10471198536, 45783025416, 200176267464, 875226954888, 3826738469448, 16731577137672, 73155162229704, 319854949515144, 1398495821923656
Offset: 0

Views

Author

Gerhard Kirchner, May 18 2022

Keywords

Comments

Tiling algorithm see A351322.

Examples

			a(3)=48
Number of tilings without a 2 X 2 square: 44, see A353878.
Number of other tilings: 4
   ___ _   ___ _   _ ___   _ ___
  |   | | |   |_| | |   | |_|   |
  |___|_| |___|_| |_|___| |_|___|
		

Crossrefs

Programs

Formula

G.f.: (1 - x) / (1 - 3*x - 6*x^2).
a(n) = 3*a(n-1) + 6*a(n-2).

A354132 Number of tilings of a 3 X n rectangle using 2 X 2 and 1 X 1 tiles, right trominoes and dominoes.

Original entry on oeis.org

1, 3, 48, 405, 4185, 40320, 397755, 3892293, 38193444, 374425263, 3671810235, 36003770640, 353046480345, 3461866214283, 33946152068808, 332866572321933, 3263999126947497, 32005882711563552, 313840950402409011, 3077438640586986141, 30176522977460549436
Offset: 0

Views

Author

Gerhard Kirchner, May 18 2022

Keywords

Comments

Tiling algorithm see A351322.

Examples

			a(2) = 48, see 2 X 3, A354131.
		

Crossrefs

Programs

Formula

G.f.: (1 - 3*x - 8*x^2 + 3*x^3 - x^4) / (1 - 6*x - 38*x^2 + 68*x^4 - 24*x^5 + 3*x^6).
a(n) = 6*a(n-1) + 38*a(n-2) - 68*a(n-4) + 24*a(n-5) - 3*a(n-6).
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