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.

A233026 T(n,k)=Number of nXk 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally, vertically, diagonally or antidiagonally, and top left element zero.

Original entry on oeis.org

1, 3, 3, 9, 15, 9, 27, 81, 81, 27, 81, 435, 849, 435, 81, 243, 2337, 8835, 8835, 2337, 243, 729, 12555, 92067, 179999, 92067, 12555, 729, 2187, 67449, 959385, 3685017, 3685017, 959385, 67449, 2187, 6561, 362355, 9997413, 75489671, 149128385
Offset: 1

Views

Author

R. H. Hardin, Dec 03 2013

Keywords

Comments

Table starts
.....1........3...........9.............27................81
.....3.......15..........81............435..............2337
.....9.......81.........849...........8835.............92067
....27......435........8835.........179999...........3685017
....81.....2337.......92067........3685017.........149128385
...243....12555......959385.......75489671........6050598339
...729....67449.....9997413.....1546718177......245698677999
..2187...362355...104179551....31692006853.....9979662714381
..6561..1946673..1085618895...649369155341...405380056659145
.19683.10458075.11312857317.13305594622397.16467175046293207

Examples

			Some solutions for n=4 k=4
..0..2..2..2....0..0..2..2....0..0..0..2....0..0..0..1....0..0..0..2
..2..0..0..2....2..2..0..0....0..2..0..0....0..0..0..1....2..2..2..2
..2..2..0..0....2..2..0..0....0..2..2..2....0..1..1..1....2..2..0..0
..2..2..2..0....0..0..0..0....2..2..0..0....0..0..0..0....2..2..0..1
		

Crossrefs

Column 1 is A000244(n-1)

Formula

Empirical for column k:
k=1: a(n) = 3*a(n-1)
k=2: a(n) = 5*a(n-1) +2*a(n-2)
k=3: a(n) = 11*a(n-1) -5*a(n-2) -11*a(n-3) +2*a(n-4)
k=4: [order 8]
k=5: [order 20]
k=6: [order 50]