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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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

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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).
Showing 1-2 of 2 results.