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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A266131 T(n,k) = Number of n X k integer arrays with each element equal to the number of horizontal, diagonal and antidiagonal neighbors exactly one smaller than itself.

Original entry on oeis.org

1, 3, 1, 4, 9, 1, 5, 25, 20, 1, 9, 49, 77, 61, 1, 16, 149, 117, 385, 189, 1, 25, 625, 278, 572, 2099, 544, 1, 39, 2141, 1959, 3851, 4336, 9083, 1629, 1, 64, 5433, 11044, 44623, 62104, 19750, 48188, 4973, 1, 105, 17269, 36730, 347576, 1285961, 326145, 102201, 249446
Offset: 1

Views

Author

R. H. Hardin, Dec 21 2015

Keywords

Comments

Table starts
.1.....3.......4........5.........9.........16..........25.........39
.1.....9......25.......49.......149........625........2141.......5433
.1....20......77......117.......278.......1959.......11044......36730
.1....61.....385......572......3851......44623......347576....1650710
.1...189....2099.....4336.....62104....1285961....16386099..124675418
.1...544....9083....19750....326145...13689944...325554385.3901509248
.1..1629...48188...102201...4176690..311260836.10444421518
.1..4973..249446...620508..50677045.6688962679
.1.15040.1166325..3041449.367191341
.1.45739.6288299.16217839

Examples

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

Crossrefs

Column 2 is A196212.
Row 1 is A195971.

Formula

Empirical for column k:
k=1: a(n) = a(n-1),
k=2: [order 10],
k=3: [order 26] for n>27,
Empirical for row n:
n=1: a(n) = a(n-1) +a(n-3) +a(n-4),
n=2: [order 17],
n=3: [order 77].

A196685 T(n,k)=Number of nXk 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 4,0,1,2,3 for x=0,1,2,3,4.

Original entry on oeis.org

1, 3, 3, 4, 9, 4, 5, 20, 20, 5, 9, 61, 58, 61, 9, 16, 189, 292, 292, 189, 16, 25, 544, 1235, 2245, 1235, 544, 25, 39, 1629, 5186, 15395, 15395, 5186, 1629, 39, 64, 4973, 22461, 109528, 188078, 109528, 22461, 4973, 64, 105, 15040, 96256, 796557, 2169685
Offset: 1

Views

Author

R. H. Hardin Oct 05 2011

Keywords

Comments

Every 0 is next to 0 4's, every 1 is next to 1 0's, every 2 is next to 2 1's, every 3 is next to 3 2's, every 4 is next to 4 3's
Table starts
...1.....3.......4.........5...........9............16..............25
...3.....9......20........61.........189...........544............1629
...4....20......58.......292........1235..........5186...........22461
...5....61.....292......2245.......15395........109528..........796557
...9...189....1235.....15395......188078.......2169685........25142624
..16...544....5186....109528.....2169685......39696088.......741925729
..25..1629...22461....796557....25142624.....741925729.....23029545105
..39..4973...96256...5702355...291420839...14189246566....718199634805
..64.15040..413032..40479328..3417608122..269528695666..22138818455076
.105.45739.1780597.289195575.40048090008.5096101360077.682005890331480

Examples

			Some solutions for n=6 k=4
..0..0..1..1....1..1..0..1....0..0..0..1....0..0..0..0....1..0..0..0
..1..1..2..0....0..1..1..1....0..0..0..2....1..1..2..0....1..2..1..1
..2..1..0..0....0..1..1..0....0..0..0..1....2..2..1..0....0..2..1..2
..0..1..2..0....0..1..1..0....1..2..1..2....1..2..2..0....1..1..0..0
..2..1..1..0....0..2..1..0....1..0..2..0....0..1..1..2....1..1..0..0
..1..0..2..1....0..0..2..1....2..1..1..0....1..2..0..1....0..1..2..1
		

Crossrefs

Column 1 is A195971
Column 2 is A196212
Showing 1-2 of 2 results.