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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A281765 T(n,k)=Number of nXk 0..1 arrays with no element unequal to a strict majority of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

Original entry on oeis.org

0, 0, 0, 2, 4, 0, 2, 14, 10, 0, 5, 40, 47, 20, 0, 8, 110, 152, 90, 38, 0, 15, 280, 609, 560, 201, 68, 0, 26, 698, 2138, 2808, 1872, 374, 120, 0, 46, 1696, 7466, 13968, 12191, 5948, 672, 208, 0, 80, 4052, 25798, 68362, 85844, 49986, 18358, 1172, 358, 0, 139, 9564, 87397
Offset: 1

Views

Author

R. H. Hardin, Jan 29 2017

Keywords

Comments

Table starts
.0...0....2......2........5.........8..........15...........26.............46
.0...4...14.....40......110.......280.........698.........1696...........4052
.0..10...47....152......609......2138........7466........25798..........87397
.0..20...90....560.....2808.....13968.......68362.......323280........1529974
.0..38..201...1872....12191.....85844......589990......3845590.......25703392
.0..68..374...5948....49986....502276.....4845178.....43943360......414035752
.0.120..672..18358...201450...2848436....38998648....491290688.....6531040026
.0.208.1172..55048...795220..15817652...306847534...5380228500...100838834642
.0.358.2015.162120..3098932..86332266..2376142873..58064622712..1533079336619
.0.612.3442.471340.11944444.465260812.18172170592.619082149716.23019093115418

Examples

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

Crossrefs

Column 2 is A279262.
Row 1 is A006367(n-1).

Formula

Empirical for column k:
k=1: a(n) = a(n-1)
k=2: a(n) = 3*a(n-1) -a(n-2) -3*a(n-3) +a(n-4) +a(n-5)
k=3: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +4*a(n-4) -a(n-6) for n>11
k=4: [order 29] for n>32
k=5: [order 48] for n>57
Empirical for row n:
n=1: a(n) = 2*a(n-1) +a(n-2) -2*a(n-3) -a(n-4) for n>5
n=2: [order 9]
n=3: [order 40] for n>41

A280440 T(n,k)=Number of nXk 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

Original entry on oeis.org

0, 0, 0, 1, 4, 1, 2, 10, 10, 2, 5, 20, 21, 20, 5, 10, 38, 42, 42, 38, 10, 20, 68, 77, 80, 77, 68, 20, 38, 120, 136, 138, 138, 136, 120, 38, 71, 208, 236, 232, 225, 232, 236, 208, 71, 130, 358, 404, 386, 360, 360, 386, 404, 358, 130, 235, 612, 687, 640, 574, 548, 574, 640, 687
Offset: 1

Views

Author

R. H. Hardin, Jan 03 2017

Keywords

Comments

Table starts
...0...0....1....2....5...10...20...38...71..130...235...420...744..1308..2285
...0...4...10...20...38...68..120..208..358..612..1042..1768..2992..5052..8514
...1..10...21...42...77..136..236..404..687.1162..1959..3294..5528..9262.15497
...2..20...42...80..138..232..386..640.1062.1764..2934..4884..8134.13548.22562
...5..38...77..138..225..360..574..920.1487.2422..3971..6542.10814.17914.29713
..10..68..136..232..360..548..834.1284.2008.3188..5128..8332.13638.22436.37032
..20.120..236..386..574..834.1211.1784.2684.4128..6478.10334.16693.27208.44620
..38.208..404..640..920.1284.1784.2512.3620.5360..8152.12692.20136.32400.52660
..71.358..687.1062.1487.2008.2684.3620.4989.7078.10365.15642.24224.38290.61451
.130.612.1162.1764.2422.3188.4128.5360.7078.9604.13474.19576.29384.45340.71490

Examples

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

Crossrefs

Column 1 is A001629(n-1).
Column 2 is A279262.

Formula

Empirical for column k:
k=1: a(n) = 2*a(n-1) +a(n-2) -2*a(n-3) -a(n-4)
k=2: a(n) = 3*a(n-1) -a(n-2) -3*a(n-3) +a(n-4) +a(n-5)
k=3: a(n) = 3*a(n-1) -a(n-2) -3*a(n-3) +a(n-4) +a(n-5) for n>6
k=4: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +4*a(n-4) -a(n-6) for n>7
k=5: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +4*a(n-4) -a(n-6) for n>7
k=6: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +4*a(n-4) -a(n-6) for n>7
k=7: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +4*a(n-4) -a(n-6) for n>7
Showing 1-2 of 2 results.