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.

A233106 Number of n X 1 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.

Original entry on oeis.org

1, 2, 6, 23, 99, 452, 2136, 10313, 50469, 249062, 1235466, 6147803, 30650439, 152986472, 764135196, 3818284493, 19084248009, 95399716682, 476934013326, 2384476356383, 11921800651179, 59607259863692, 298031069141856
Offset: 1

Views

Author

R. H. Hardin, Dec 04 2013

Keywords

Comments

Column 1 of A233113.

Examples

			Some solutions for n=7:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....0....0....1....0....1....1....1....0....1....1....0....1....0....1
..2....2....0....1....5....1....5....2....1....1....5....5....1....0....1....2
..1....4....1....5....1....5....2....0....1....5....1....5....2....4....2....5
..5....0....1....1....1....4....0....3....5....5....1....1....1....2....1....5
..1....2....2....0....2....5....3....5....1....2....1....0....5....4....3....2
..5....2....0....1....5....4....1....2....0....5....5....0....2....2....3....5
		

Formula

Empirical: a(n) = 9*a(n-1) - 23*a(n-2) + 15*a(n-3).
Conjectures from Colin Barker, Feb 19 2018: (Start)
G.f.: x*(1 - 7*x + 11*x^2) / ((1 - x)*(1 - 3*x)*(1 - 5*x)).
a(n) = (75 + 10*3^n + 3*5^n) / 120.
(End)

A233107 Number of n X 2 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.

Original entry on oeis.org

2, 19, 313, 6046, 123352, 2565169, 53692063, 1126297996, 23643610702, 496455294319, 10425137467813, 218924920833946, 4597402575582052, 96545308753707469, 2027450466493247563, 42576452675015933896
Offset: 1

Views

Author

R. H. Hardin, Dec 04 2013

Keywords

Comments

Column 2 of A233113.

Examples

			Some solutions for n=5:
..0..0....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1
..1..1....0..2....1..0....1..0....2..5....1..2....2..2....0..2....2..1....0..0
..2..5....4..5....5..1....0..4....0..2....5..5....1..0....1..2....1..3....0..1
..4..2....4..4....2..1....2..2....2..4....5..4....5..3....1..5....5..5....4..2
..5..4....5..5....1..2....1..5....4..5....2..5....2..5....1..1....4..5....0..1
		

Crossrefs

Cf. A233113.

Formula

Empirical: a(n) = 29*a(n-1) - 175*a(n-2) + 147*a(n-3).
Conjectures from Colin Barker, Mar 19 2018: (Start)
G.f.: x*(2 - 7*x)*(1 - 16*x) / ((1 - x)*(1 - 7*x)*(1 - 21*x)).
a(n) = (105 + 18*7^n + 5*21^n) / 168.
(End)

A233108 Number of n X 3 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.

Original entry on oeis.org

6, 313, 24912, 2154065, 189286871, 16683923848, 1471365099497, 129774107522700, 11446271884607256, 1009582054691903383, 89047037607095248482, 7854117302435219663735, 692748031461206544348041
Offset: 1

Views

Author

R. H. Hardin, Dec 04 2013

Keywords

Examples

			Some solutions for n=3:
..0..1..0....0..1..1....0..0..1....0..1..5....0..1..5....0..1..0....0..1..1
..2..1..0....2..1..2....2..0..2....2..2..4....1..2..1....0..2..1....2..0..0
..0..1..0....1..0..0....4..0..2....0..1..0....0..0..0....2..1..3....5..1..2
		

Crossrefs

Column 3 of A233113.

Formula

Empirical: a(n) = 111*a(n-1) - 2128*a(n-2) + 10532*a(n-3) - 17559*a(n-4) + 9045*a(n-5).
Empirical g.f.: x*(6 - 353*x + 2937*x^2 - 8295*x^3 + 7230*x^4) / ((1 - x)*(1 - 18*x + 27*x^2)*(1 - 92*x + 335*x^2)). - Colin Barker, Oct 07 2018

A233109 Number of nX4 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.

Original entry on oeis.org

23, 6046, 2154065, 794723482, 294285758398, 109015274761891, 40385221182281560, 14960955484170769147, 5542380989283805407733, 2053210330075493118514936, 760624844506193044187974495
Offset: 1

Views

Author

R. H. Hardin, Dec 04 2013

Keywords

Comments

Column 4 of A233113

Examples

			Some solutions for n=2
..0..1..5..4....0..1..2..4....0..1..2..5....0..1..2..2....0..1..2..5
..2..5..4..2....1..5..2..5....4..3..0..3....1..0..1..2....3..5..4..5
		

Formula

Empirical: a(n) = 445*a(n-1) -29415*a(n-2) +684239*a(n-3) -6544703*a(n-4) +26009211*a(n-5) -37153497*a(n-6) +17033721*a(n-7)

A233110 Number of nX5 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.

Original entry on oeis.org

99, 123352, 189286871, 294285758398, 457873555330159, 712427482567592092, 1108502928092713640626, 1724777533707727108574193, 2683671364004795423834363994, 4175664311828036646078204783047
Offset: 1

Views

Author

R. H. Hardin, Dec 04 2013

Keywords

Comments

Column 5 of A233113

Examples

			Some solutions for n=2
..0..0..1..5..2....0..1..5..4..0....0..1..1..1..2....0..1..0..1..5
..0..3..5..5..2....0..0..2..0..1....1..5..5..2..5....2..1..0..0..3
		

Formula

Empirical: a(n) = 1903*a(n-1) -587832*a(n-2) +77760886*a(n-3) -5287016185*a(n-4) +188909127665*a(n-5) -3121291574501*a(n-6) +5961157912045*a(n-7) +488488284983722*a(n-8) -6216213294870140*a(n-9) +30096051456844829*a(n-10) -50425593642643659*a(n-11) -57028414169574032*a(n-12) +289749791197635300*a(n-13) -320983517286000000*a(n-14) +114316383888000000*a(n-15)

A233111 Number of nX6 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.

Original entry on oeis.org

452, 2565169, 16683923848, 109015274761891, 712427482567592092, 4655818309443587944819, 30426461543542804692390703, 198841429156093687790582460286, 1299458167307093973096933933936847
Offset: 1

Views

Author

R. H. Hardin, Dec 04 2013

Keywords

Comments

Column 6 of A233113

Examples

			Some solutions for n=2
..0..1..0..2..4..5....0..0..0..1..2..1....0..0..1..2..2..0....0..0..1..1..5..5
..0..0..0..4..3..1....0..0..4..0..1..5....0..1..2..1..0..1....0..0..2..5..1..5
		

A233112 Number of nX7 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.

Original entry on oeis.org

2136, 53692063, 1471365099497, 40385221182281560, 1108502928092713640626, 30426461543542804692390703, 835153023014356911992288011287, 22923486223269810222694953768125080
Offset: 1

Views

Author

R. H. Hardin, Dec 04 2013

Keywords

Comments

Column 7 of A233113

Examples

			Some solutions for n=2
..0..0..0..1..0..1..5....0..0..0..1..2..4..0....0..0..0..1..2..5..3
..0..0..0..0..2..5..3....1..0..0..0..0..4..4....4..0..0..2..5..5..4
		

A233105 Number of n X n 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.

Original entry on oeis.org

1, 19, 24912, 794723482, 457873555330159, 4655818309443587944819, 835153023014356911992288011287, 2642740111638617064845250032401005032917, 147523503812676026261878057522783598121057848912309
Offset: 1

Views

Author

R. H. Hardin, Dec 04 2013

Keywords

Comments

Diagonal of A233113

Examples

			Some solutions for n=3
..0..1..5....0..1..0....0..1..2....0..1..2....0..1..5....0..0..0....0..1..0
..4..2..4....1..5..4....4..3..1....2..1..2....2..1..1....0..1..1....4..2..2
..0..2..4....0..4..4....5..1..1....4..3..4....2..2..1....0..0..2....2..5..4
		
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