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.

A186161 1/4 the number of n X 2 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Original entry on oeis.org

1, 7, 48, 321, 2175, 14748, 99933, 677283, 4590168, 31108893, 210834267, 1428886932, 9683993481, 65631317487, 444803049600, 3014563174089, 20430595384935, 138464249604684, 938413592805957, 6359909317239723
Offset: 1

Views

Author

R. H. Hardin, Feb 13 2011

Keywords

Comments

Column 2 of A186168.

Examples

			Some solutions for 4 X 2 with a(1,1)=0:
..0..0....0..1....0..0....0..0....0..3....0..2....0..0....0..2....0..2....0..0
..2..2....0..1....2..3....1..1....0..3....0..2....0..2....0..2....0..2....0..0
..0..2....3..3....2..3....3..3....2..0....0..2....3..2....3..3....1..1....2..2
..0..0....0..0....1..1....3..3....2..0....0..2....3..3....3..3....1..1....0..0
		

Crossrefs

Cf. A186168.

Formula

Empirical: a(n) = 5*a(n-1) + 11*a(n-2) + 9*a(n-3) - 9*a(n-4) - 27*a(n-5).
Empirical g.f.: x*(1 + 2*x + 2*x^2 - 5*x^3 - 12*x^4) / (1 - 5*x - 11*x^2 - 9*x^3 + 9*x^4 + 27*x^5). - Colin Barker, Apr 17 2018

A186162 1/4 the number of nX3 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Original entry on oeis.org

1, 48, 702, 14364, 253341, 4762206, 87054174, 1610684397, 29645381115, 546876640548, 10078456022415, 185816448936792, 3425262221153151, 63144918326035629, 1164039832228952691, 21458721711659114403
Offset: 1

Views

Author

R. H. Hardin Feb 13 2011

Keywords

Comments

Column 3 of A186168

Examples

			Some solutions for 4X3 with a(1,1)=0
..0..0..0....0..1..0....0..0..0....0..2..2....0..2..2....0..3..3....0..0..3
..0..3..3....0..1..0....2..2..0....0..2..3....0..3..1....0..2..2....0..1..3
..3..1..1....3..1..3....3..2..2....0..3..3....3..3..1....0..1..3....2..1..1
..3..2..2....3..1..3....3..3..3....1..1..1....1..1..1....1..1..3....2..0..0
		

Formula

Empirical: a(n)=12*a(n-1)+138*a(n-2)-297*a(n-3)-1095*a(n-4)-588*a(n-5)+4871*a(n-6)+10632*a(n-7)-24375*a(n-8)+40893*a(n-9)-59724*a(n-10)-68247*a(n-11)-358891*a(n-12)+1270395*a(n-13)+391440*a(n-14)-2188134*a(n-15)+133083*a(n-16)+1270323*a(n-17)+3453273*a(n-18)+1073817*a(n-19)-5417199*a(n-20)-4448358*a(n-21)-13463172*a(n-22)-12754584*a(n-23)

A186163 1/4 the number of nX4 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Original entry on oeis.org

4, 321, 14364, 751266, 37402872, 1899336597, 95752776009, 4840082975532, 244420512852030, 12347377339339755, 623671780419814416, 31503432697236966789, 1591300459563274835532, 80380228276030331585859
Offset: 1

Views

Author

R. H. Hardin Feb 13 2011

Keywords

Comments

Column 4 of A186168

Examples

			Some solutions for 6X4 with a(1,1)=0
..0..0..0..1....0..0..2..2....0..0..0..3....0..0..1..1....0..0..3..3
..0..2..2..1....0..2..2..1....0..2..2..3....0..2..2..1....0..2..2..2
..0..0..2..3....0..0..1..1....0..0..3..0....0..0..1..1....0..0..3..1
..2..0..0..3....2..0..2..2....2..0..3..0....2..0..3..3....2..0..3..1
..2..2..0..0....2..3..3..1....2..2..2..0....2..2..2..2....2..0..2..2
..0..0..2..2....0..0..0..1....0..0..1..1....0..0..1..1....2..2..0..0
		

A186164 1/4 the number of nX5 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Original entry on oeis.org

7, 2175, 253341, 37402872, 5033988714, 704281652979, 96951738076992, 13435825601048421, 1856827788245959473, 256908205340960558187, 35528479510856892673200, 4914300705034627821533085
Offset: 1

Views

Author

R. H. Hardin Feb 13 2011

Keywords

Comments

Column 5 of A186168

Examples

			Some solutions for 4X5 with a(1,1)=0
..0..0..0..1..1....0..0..0..0..0....0..0..0..3..3....0..0..0..2..2
..0..2..0..1..2....0..2..1..1..1....0..2..0..1..3....0..2..0..2..1
..1..2..2..1..2....0..2..2..3..3....0..2..2..1..1....0..2..0..3..1
..1..1..0..0..2....3..3..3..0..0....0..3..3..0..0....0..2..0..3..3
		

A186160 1/4 the number of n X n 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Original entry on oeis.org

0, 7, 702, 751266, 5033988714, 268995986029278
Offset: 1

Views

Author

R. H. Hardin Feb 13 2011

Keywords

Comments

Diagonal of A186168

Examples

			Some solutions for 4X4 with a(1,1)=0
..0..2..0..2....0..0..2..0....0..2..1..1....0..0..2..2....0..2..2..1
..0..2..0..2....0..0..2..0....0..2..0..0....0..2..1..2....0..0..0..1
..1..2..3..3....2..3..3..3....2..1..1..0....2..2..1..0....2..3..3..1
..1..1..1..1....2..3..2..2....2..2..1..0....3..3..3..0....2..3..0..0
		

A186165 1/4 the number of nX6 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Original entry on oeis.org

19, 14748, 4762206, 1899336597, 704281652979, 268995986029278, 101554003879403823, 38514280297010210802
Offset: 1

Views

Author

R. H. Hardin Feb 13 2011

Keywords

Comments

Column 6 of A186168

Examples

			Some solutions for 4X6 with a(1,1)=0
..0..0..0..2..2..2....0..0..0..2..2..0....0..0..0..2..2..0....0..0..0..2..2..0
..0..2..0..0..0..2....0..2..0..0..2..0....0..2..0..0..0..0....0..2..0..0..3..0
..3..2..1..2..0..3....3..2..1..1..2..0....0..2..2..2..2..2....1..2..2..3..3..0
..3..1..1..2..0..3....3..0..0..0..2..0....0..0..0..0..1..1....1..0..0..3..2..2
		

A186166 1/4 the number of n X 7 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Original entry on oeis.org

40, 99933, 87054174, 95752776009, 96951738076992, 101554003879403823
Offset: 1

Views

Author

R. H. Hardin Feb 13 2011

Keywords

Comments

Column 7 of A186168.

Examples

			Some solutions for 4 X 7 with a(1,1) = 0
..0..0..2..0..0..0..1....0..0..2..0..0..3..0....0..0..2..0..0..0..0
..0..0..2..0..2..2..1....0..0..2..0..3..3..0....0..0..2..0..2..2..1
..2..2..0..2..3..3..1....2..2..0..2..3..0..1....2..2..0..1..2..1..1
..0..0..0..2..3..2..2....0..0..0..2..0..0..1....0..0..0..1..1..3..3
		

Crossrefs

Cf. A186168.

A186167 1/4 the number of nX8 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Original entry on oeis.org

97, 677283, 1610684397, 4840082975532, 13435825601048421, 38514280297010210802
Offset: 1

Views

Author

R. H. Hardin Feb 13 2011

Keywords

Comments

Column 8 of A186168

Examples

			Some solutions for 3X8 with a(1,1)=0
..0..0..0..0..2..1..1..0....0..0..0..0..3..0..3..3....0..0..0..0..0..3..3..0
..0..1..1..2..2..3..1..0....0..1..1..0..3..0..0..3....0..1..1..2..2..1..0..0
..0..0..0..0..0..3..3..0....0..0..0..0..3..3..0..0....0..0..0..0..2..1..3..3
		
Showing 1-8 of 8 results.