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 1-8 of 8 results.

A199126 Number of nX1 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and no element equal to any horizontal or vertical neighbor.

Original entry on oeis.org

1, 1, 1, 3, 6, 5, 19, 37, 29, 124, 240, 182, 834, 1614, 1198, 5746, 11137, 8142, 40336, 78332, 56620, 287358, 559134, 400598, 2071558, 4038130, 2872754, 15079270, 29443040, 20824778, 110653854, 216379650, 152303410, 817542980, 1600817660
Offset: 1

Views

Author

R. H. Hardin Nov 03 2011

Keywords

Comments

Column 1 of A199133

Examples

			All solutions for n=5
..0....0....0....0....0....0
..1....1....1....1....1....1
..2....2....2....0....2....0
..0....1....0....2....1....1
..2....2....1....1....0....2
		

Formula

Conjecture: a(3n) = A190917(n). - R. J. Mathar, Nov 01 2015

A199127 Number of n X 2 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and no element equal to any horizontal or vertical neighbor.

Original entry on oeis.org

1, 2, 2, 12, 30, 30, 210, 560, 560, 4200, 11550, 11550, 90090, 252252, 252252, 2018016, 5717712, 5717712, 46558512, 133024320, 133024320, 1097450640, 3155170590, 3155170590, 26293088250, 75957810500, 75957810500, 638045608200
Offset: 1

Views

Author

R. H. Hardin, Nov 03 2011

Keywords

Comments

Column 2 of A199133.
a(n) is the last term in row n of triangle in A286030 (see also formulas below). Bob Selcoe, Sep 26 2021

Examples

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

Crossrefs

Cf. A286030.

Formula

Conjecture: a(3n+2) = a(3n+3) = A208881(n+1). - R. J. Mathar, Nov 01 2015
Conjecture: -(458*n-1205) *(n+2) *(n+1)*a(n) +(-208*n^3+2578*n^2-4613*n-2410) *a(n-1) +9*(-339*n-638) *a(n-2) +27*(n-2) *(458*n^2-289*n-1146) *a(n-3) +54*(n-2) *(n-3) *(104*n-1081) *a(n-4)=0. - R. J. Mathar, Nov 01 2015
Conjecture: (n+2)*(n+1)*a(n) +(5*n^2-2)*a(n-1) +3*(5*n^2-15*n+3) *a(n-2) +3*(n^2 -60*n +81)*a(n-3) +135*(-n^2+3*n-1)*a(n-4) -405*(n-2)*(n-4) *a(n-5) -810*(n-4) *(n-5) *a(n-6)=0. - R. J. Mathar, Nov 01 2015
From Bob Selcoe, Sep 26 2021: (Start)
When n == 0 (mod 3), a(n) = n!/(3*(n/3)!^3);
when n == 1 (mod 3), a(n) = n!/(((n+2)/3)!*((n-1)/3)!^2);
when n == 2 (mod 3), a(n) = n!/(((n-2)/3)!*((n+1)/3)!^2).
(End)

A199128 Number of nX3 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and no element equal to any horizontal or vertical neighbor.

Original entry on oeis.org

1, 2, 6, 19, 70, 264, 1038, 4155, 16896, 69584, 289146, 1211873, 5111178, 21686612, 92453594, 395888507, 1701506820, 7337867736, 31739124866, 137656095241, 598476364166, 2607710997676, 11385288787534, 49800060551081
Offset: 1

Views

Author

R. H. Hardin Nov 03 2011

Keywords

Comments

Column 3 of A199133

Examples

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

A199129 Number of nX4 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and no element equal to any horizontal or vertical neighbor.

Original entry on oeis.org

3, 12, 19, 258, 1409, 2836, 48320, 295092, 629776, 11499816, 73045294, 159683856, 3012721252, 19537447260, 43276955012, 832789320948, 5471578311520, 12222775051564, 238366172778672, 1580313985819656, 3551105861275344
Offset: 1

Views

Author

R. H. Hardin Nov 03 2011

Keywords

Comments

Column 4 of A199133

Examples

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

A199130 Number of nX5 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and no element equal to any horizontal or vertical neighbor.

Original entry on oeis.org

6, 30, 70, 1409, 11475, 33970, 887966, 8181546, 26354800, 739462036, 7166709232, 23742940530, 690068431668, 6837489856538, 23031293598718, 682253330136338, 6857414650447522, 23326710623207736, 700022706564351432
Offset: 1

Views

Author

R. H. Hardin Nov 03 2011

Keywords

Comments

Column 5 of A199133

Examples

			Some solutions for n=6
..0..1..2..1..2....0..1..2..1..0....0..1..0..2..0....0..1..0..1..0
..1..2..1..0..1....2..0..1..0..2....1..2..1..0..2....1..0..1..0..1
..0..1..0..2..0....0..1..2..1..0....0..1..0..2..0....2..1..2..1..2
..2..0..2..1..2....1..2..1..0..1....1..2..1..0..1....1..2..0..2..0
..0..2..0..2..1....2..0..2..1..2....2..0..2..1..2....2..1..2..0..2
..1..0..2..1..0....0..2..1..2..0....1..2..0..2..1....0..2..1..2..0
		

A199131 Number of nX6 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and no element equal to any horizontal or vertical neighbor.

Original entry on oeis.org

5, 30, 264, 2836, 33970, 438502, 5926852, 82908094, 1187201812, 17307138986, 255687902462, 3817658150424, 57485010058768, 871667490461400, 13295046323445896, 203799010704532580, 3137556683409570358
Offset: 1

Views

Author

R. H. Hardin Nov 03 2011

Keywords

Comments

Column 6 of A199133

Examples

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

A199132 Number of nX7 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and no element equal to any horizontal or vertical neighbor.

Original entry on oeis.org

19, 210, 1038, 48320, 887966, 5926852, 358599045, 7633754680, 56435001338, 3718131446504, 84113596169937, 647071266317908, 44371190146396476, 1031280656608709860, 8107333731404729122, 567373010032314560752
Offset: 1

Views

Author

R. H. Hardin Nov 03 2011

Keywords

Comments

Column 7 of A199133

Examples

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

A199125 Number of n X n 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and no element equal to any horizontal or vertical neighbor.

Original entry on oeis.org

1, 2, 6, 258, 11475, 438502, 358599045, 247746055048, 141388449764548
Offset: 1

Views

Author

R. H. Hardin Nov 03 2011

Keywords

Comments

Diagonal of A199133

Examples

			Some solutions for n=5
..0..1..0..1..0....0..1..2..1..2....0..1..2..1..2....0..1..0..2..1
..2..0..1..0..2....2..0..1..0..1....1..2..1..2..0....1..0..2..0..2
..1..2..0..2..1....0..2..0..1..2....2..0..2..0..1....0..2..1..2..1
..0..1..2..1..2....1..0..2..0..1....0..2..1..2..0....1..0..2..1..0
..1..2..0..2..1....2..1..0..2..0....1..0..2..0..1....0..2..1..0..2
		
Showing 1-8 of 8 results.