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 1-2 of 2 results.

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).
Showing 1-2 of 2 results.