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 1-7 of 7 results.

A233020 Number of n X 2 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

3, 15, 81, 435, 2337, 12555, 67449, 362355, 1946673, 10458075, 56183721, 301834755, 1621541217, 8711375595, 46799960409, 251422553235, 1350712686993, 7256408541435, 38983468081161, 209430157488675, 1125117723605697
Offset: 1

Views

Author

R. H. Hardin, Dec 03 2013

Keywords

Examples

			Some solutions for n=5:
..0..2....0..0....0..0....0..1....0..0....0..0....0..1....0..2....0..0....0..0
..2..2....1..1....2..2....1..1....1..1....0..2....0..1....2..0....1..1....0..0
..3..2....1..1....2..3....0..0....0..0....2..2....0..1....2..0....1..1....1..1
..3..2....1..3....3..3....2..2....1..1....2..3....0..1....0..2....3..3....3..1
..2..3....3..3....3..2....0..0....3..1....2..3....0..1....0..2....2..3....3..1
		

Crossrefs

Column 2 of A233026.

Formula

Empirical: a(n) = 5*a(n-1) + 2*a(n-2).
Conjectures from Colin Barker, Oct 06 2018: (Start)
G.f.: 3*x / (1 - 5*x - 2*x^2).
a(n) = sqrt(3/11)*(((5+sqrt(33))/2)^n - ((5-sqrt(33))/2)^n) = 3*A015535(n).
(End)

A233019 Number of n X n 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, 15, 849, 179999, 149128385, 487651369463, 6338787392715565, 328918675019714663095, 68332288847776936953486283, 56955693489584720827393016043135
Offset: 1

Views

Author

R. H. Hardin, Dec 03 2013

Keywords

Comments

Diagonal of A233026

Examples

			Some solutions for n=4
..0..0..2..3....0..0..2..3....0..0..2..2....0..2..2..0....0..2..0..0
..0..2..2..2....2..0..2..2....2..0..0..2....0..2..0..2....2..0..2..2
..0..2..3..3....2..2..0..2....0..0..0..0....0..2..2..2....0..2..0..2
..0..2..2..3....0..0..2..2....0..0..0..0....0..2..0..2....2..2..0..0
		

A233021 Number of n X 3 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

9, 81, 849, 8835, 92067, 959385, 9997413, 104179551, 1085618895, 11312857317, 117887355777, 1228463178219, 12801387988827, 133398816787089, 1390102724464989, 14485777543658775, 150951255149241255
Offset: 1

Views

Author

R. H. Hardin, Dec 03 2013

Keywords

Examples

			Some solutions for n=5:
..0..1..0....0..0..1....0..0..0....0..1..0....0..1..3....0..0..0....0..1..0
..0..1..1....1..1..1....2..2..2....1..1..0....0..1..1....0..2..0....0..1..1
..0..1..0....3..3..3....3..2..0....1..0..0....1..1..1....2..0..2....1..1..1
..1..1..1....1..1..1....3..2..2....0..0..0....1..3..3....2..0..2....1..3..3
..1..0..0....3..3..1....2..2..2....0..0..2....1..1..1....2..2..2....3..3..2
		

Crossrefs

Column 3 of A233026.

Formula

Empirical: a(n) = 11*a(n-1) - 5*a(n-2) - 11*a(n-3) + 2*a(n-4).
Empirical g.f.: 3*x*(3 - 6*x + x^2) / (1 - 11*x + 5*x^2 + 11*x^3 - 2*x^4). - Colin Barker, Oct 07 2018

A233022 Number of nX4 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

27, 435, 8835, 179999, 3685017, 75489671, 1546718177, 31692006853, 649369155341, 13305594622397, 272632154901327, 5586243967145293, 114462368539181387, 2345338645585949507, 48056085480976430831, 984671171688465647531
Offset: 1

Views

Author

R. H. Hardin, Dec 03 2013

Keywords

Comments

Column 4 of A233026

Examples

			Some solutions for n=4
..0..2..2..2....0..0..2..2....0..2..0..0....0..0..1..3....0..0..0..2
..0..2..2..2....2..2..2..2....2..0..2..0....0..0..1..1....2..2..2..0
..0..0..0..2....0..2..2..0....0..2..0..2....1..0..1..1....3..2..2..0
..1..0..2..2....2..2..2..0....2..0..0..0....1..0..0..1....3..2..2..0
		

Formula

Empirical: a(n) = 23*a(n-1) -39*a(n-2) -265*a(n-3) +180*a(n-4) +655*a(n-5) -156*a(n-6) -127*a(n-7) +20*a(n-8)
Empirical: G.f.: -x*(27-186*x-117*x^2+914*x^3+20*x^4-469*x^5+129*x^6)/(-1+23*x-39*x^2-265*x^3+180*x^4+655*x^5-156*x^6-127*x^7+20*x^8) . - R. J. Mathar, May 11 2022

A233023 Number of nX5 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

81, 2337, 92067, 3685017, 149128385, 6050598339, 245698677999, 9979662714381, 405380056659145, 16467175046293207, 668927350000203943, 27173135930635192613, 1103826618460521163805, 44839633474092471048067
Offset: 1

Views

Author

R. H. Hardin, Dec 03 2013

Keywords

Comments

Column 5 of A233026

Examples

			Some solutions for n=3
..0..2..0..1..0....0..1..3..3..3....0..1..0..1..1....0..0..1..3..3
..0..0..0..0..1....1..1..3..1..1....0..1..0..1..1....1..1..1..1..3
..0..0..0..1..1....3..3..3..1..3....0..1..1..1..1....1..1..1..3..3
		

Formula

Empirical: a(n) = 59*a(n-1) -780*a(n-2) +619*a(n-3) +32493*a(n-4) -90013*a(n-5) -408784*a(n-6) +1361086*a(n-7) +1750387*a(n-8) -6258928*a(n-9) -3161760*a(n-10) +10671769*a(n-11) +1911277*a(n-12) -7549998*a(n-13) +65894*a(n-14) +2257616*a(n-15) -323424*a(n-16) -231416*a(n-17) +54784*a(n-18) +784*a(n-19) -480*a(n-20)

A233024 Number of nX6 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

243, 12555, 959385, 75489671, 6050598339, 487651369463, 39386531523609, 3183658674622011, 257414773440925415, 20815582600558673815, 1683301058522200223439, 136126239210040751513149
Offset: 1

Views

Author

R. H. Hardin, Dec 03 2013

Keywords

Comments

Column 6 of A233026

Examples

			Some solutions for n=2
..0..0..2..3..3..3....0..2..2..3..2..0....0..1..0..1..0..0....0..0..1..1..1..1
..0..0..2..3..2..3....2..0..2..3..2..2....1..0..1..1..1..1....0..0..1..3..1..3
		

Formula

Empirical recurrence of order 50 (see link above)

A233025 Number of nX7 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

729, 67449, 9997413, 1546718177, 245698677999, 39386531523609, 6338787392715565, 1021854400935817069, 164848602838755709211, 26602184763154679609107, 4293469218556492461639273
Offset: 1

Views

Author

R. H. Hardin, Dec 03 2013

Keywords

Comments

Column 7 of A233026

Examples

			Some solutions for n=2
..0..1..0..1..1..0..1....0..0..1..3..3..3..2....0..2..2..0..0..1..0
..1..0..0..1..0..1..1....1..0..1..3..2..2..3....2..2..2..0..1..0..1
		
Showing 1-7 of 7 results.