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 1-10 of 13 results. Next

A218836 Unmatched value maps: number of n X 2 binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 n X 2 array.

Original entry on oeis.org

1, 2, 7, 21, 65, 200, 616, 1897, 5842, 17991, 55405, 170625, 525456, 1618192, 4983377, 15346786, 47261895, 145547525, 448227521, 1380359512, 4250949112, 13091204281, 40315615410, 124155792775, 382349636061, 1177482265857, 3626169232672, 11167134898976
Offset: 0

Views

Author

R. H. Hardin, Nov 07 2012

Keywords

Examples

			Some solutions for n=3
..1..1....1..1....0..0....1..0....0..0....1..0....0..0....1..1....0..0....1..0
..1..1....1..1....0..1....0..1....0..0....0..0....0..0....0..0....0..1....0..0
..1..1....0..0....0..0....1..1....0..1....1..1....1..1....1..1....1..1....0..1
		

Crossrefs

Column 2 of A218842.

Programs

  • Maple
    a:= n-> (<<0|1|0>, <0|0|1>, <1|3|2>>^n. <<1, 2, 7>>)[1$2]:
    seq(a(n), n=0..30);  # Alois P. Heinz, Apr 21 2020
  • Mathematica
    LinearRecurrence[{2, 3, 1}, {1, 2, 7}, 30] (* Paolo Xausa, Jan 29 2025 *)

Formula

a(n) = 2*a(n-1) +3*a(n-2) +a(n-3).
G.f.: Q(0)/2 , where Q(k) = 1 + 1/(1- x*(4*k+2 +3*x+x^2)/(x*(4*k+4 +3*x+x^2) + 1/Q(k+1))); (continued fraction). - Sergei N. Gladkovskii, Oct 04 2013
G.f.: 1/(1-2*x-3*x^2-x^3). - Alois P. Heinz, Apr 21 2020

Extensions

a(0)=1 prepended and first g.f. adapted by Alois P. Heinz, Apr 21 2020

A218837 Unmatched value maps: number of n X 3 binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 n X 3 array.

Original entry on oeis.org

4, 20, 93, 436, 2043, 9573, 44857, 210190, 984904, 4615043, 21625074, 101330329, 474811581, 2224862385, 10425214612, 48850257184, 228901534957, 1072582125992, 5025883366023, 23550181377025, 110350957732161, 517080258425742
Offset: 1

Views

Author

R. H. Hardin, Nov 07 2012

Keywords

Comments

Column 3 of A218842.

Examples

			Some solutions for n=3:
..1..1..0....1..0..0....1..0..0....1..1..0....1..0..0....0..0..0....0..0..0
..0..0..0....1..0..0....0..0..1....0..0..1....1..0..1....1..0..0....0..0..0
..0..1..1....1..0..1....0..0..0....0..0..1....1..1..1....1..0..1....1..0..0
		

Crossrefs

Cf. A218842.

Formula

Empirical: a(n) = 4*a(n-1) + 3*a(n-2) + a(n-3).
Empirical g.f.: x*(2 + x)^2 / (1 - 4*x - 3*x^2 - x^3). - Colin Barker, Mar 10 2018

A218838 Unmatched value maps: number of n X 4 binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 n X 4 array.

Original entry on oeis.org

7, 57, 453, 3617, 28888, 230726, 1842766, 14717828, 117548611, 938839259, 7498337380, 59887849061, 478313295496, 3820200795065, 30511244937310, 243687732023270, 1946289338913085, 15544656923507264, 124152331330394548
Offset: 1

Views

Author

R. H. Hardin, Nov 07 2012

Keywords

Comments

Column 4 of A218842.

Examples

			Some solutions for n=3:
..0..0..0..0....1..1..0..0....1..0..0..0....1..1..0..0....1..0..0..1
..1..0..1..1....1..0..0..1....1..0..0..0....1..0..0..0....0..0..1..1
..1..1..0..0....1..0..0..0....0..0..1..1....1..0..1..1....1..1..1..1
		

Crossrefs

Cf. A218842.

Formula

Empirical: a(n) = 7*a(n-1) + 5*a(n-2) + 24*a(n-3) - 9*a(n-4) + 9*a(n-5) for n>6.
Empirical g.f.: x*(7 + 8*x + 19*x^2 - 7*x^3 - x^4 + 3*x^5) / (1 - 7*x - 5*x^2 - 24*x^3 + 9*x^4 - 9*x^5). - Colin Barker, Mar 10 2018

A218839 Unmatched value maps: number of nX5 binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 nX5 array.

Original entry on oeis.org

12, 156, 2050, 26635, 346501, 4507281, 58634265, 762745363, 9922198586, 129073371922, 1679056577224, 21842080049186, 284133645307551, 3696164842194424, 48081720559244098, 625473146037672596
Offset: 1

Views

Author

R. H. Hardin Nov 07 2012

Keywords

Comments

Column 5 of A218842

Examples

			Some solutions for n=3
..0..0..1..0..0....0..0..0..0..0....0..0..0..1..1....1..1..0..0..0
..1..0..1..0..1....0..0..1..0..0....0..0..0..0..0....0..0..1..0..1
..0..0..0..0..0....1..0..0..0..1....0..1..1..0..0....1..1..1..0..0
		

Formula

Empirical: a(n) = 12*a(n-1) +6*a(n-2) +103*a(n-3) -128*a(n-4) -41*a(n-5) -630*a(n-6) -523*a(n-7) +1154*a(n-8) -93*a(n-9) +762*a(n-10) -787*a(n-11) -416*a(n-12) +549*a(n-13) -178*a(n-14) +35*a(n-15) +11*a(n-16) -7*a(n-17) for n>18

A218840 Unmatched value maps: number of nX6 binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 nX6 array.

Original entry on oeis.org

21, 438, 9516, 201960, 4299802, 91513161, 1948262831, 41475009100, 882920599454, 18795714385533, 400125250527550, 8517908622924528, 181330147341356981, 3860175542316616321, 82175828913427711206, 1749367816354069818496
Offset: 1

Views

Author

R. H. Hardin Nov 07 2012

Keywords

Comments

Column 6 of A218842

Examples

			Some solutions for n=3
..0..0..1..1..1..0....0..0..0..0..1..1....1..0..0..0..0..0....1..0..1..0..0..0
..1..1..1..0..0..0....0..0..0..0..1..1....1..0..0..0..0..1....0..0..0..1..0..1
..1..1..1..0..0..1....0..0..0..0..0..0....0..1..1..0..0..1....0..0..0..0..0..1
		

A218841 Unmatched value maps: number of nX7 binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 nX7 array.

Original entry on oeis.org

37, 1220, 44129, 1530846, 53372068, 1858438456, 64756459689, 2256078606791, 78598915311375, 2738314667345978, 95400355881324823, 3323658089304061344, 115793113908855836331, 4034122981125875986810, 140545041981707228122666
Offset: 1

Views

Author

R. H. Hardin Nov 07 2012

Keywords

Comments

Column 7 of A218842

Examples

			Some solutions for n=3
..0..0..1..0..0..0..1....0..0..0..1..1..0..0....0..0..1..1..0..0..1
..1..0..0..0..0..0..0....0..1..0..0..0..0..1....0..0..0..0..1..0..0
..0..1..1..1..0..0..0....0..0..0..1..1..0..0....0..0..0..1..0..0..1
		

A218843 Unmatched value maps: number of 2 X n binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 2 X n array.

Original entry on oeis.org

1, 7, 20, 57, 156, 438, 1220, 3398, 9468, 26380, 73496, 204780, 570556, 1589672, 4429140, 12340436, 34382820, 95797176, 266909376, 743660900, 2071982512, 5772942284, 16084528900, 44814595084, 124862092120, 347889834096
Offset: 1

Views

Author

R. H. Hardin, Nov 07 2012

Keywords

Comments

Row 2 of A218842.

Examples

			Some solutions for n=3:
..0..0..0....0..0..1....1..0..0....1..0..0....1..1..0....0..0..0....0..0..0
..0..1..1....0..0..1....1..0..1....0..1..1....0..0..0....0..0..1....1..0..0
		

Crossrefs

Cf. A218842.

Formula

Empirical: a(n) = 2*a(n-1) + a(n-2) + 3*a(n-3) + 2*a(n-5) + 2*a(n-6) - 2*a(n-7) for n>9.
Empirical g.f.: x*(1 + 5*x + 5*x^2 + 7*x^3 + x^4 + 7*x^5 + x^6 - 2*x^8) / (1 - 2*x - x^2 - 3*x^3 - 2*x^5 - 2*x^6 + 2*x^7). - Colin Barker, Jul 24 2018

A218844 Unmatched value maps: number of 3Xn binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 3Xn array.

Original entry on oeis.org

1, 21, 93, 453, 2050, 9516, 44129, 204780, 950346, 4410194, 20465923, 94974721, 440743516, 2045330613, 9491634200, 44047218242, 204407115009, 948579057090, 4402010267626, 20428127976053, 94799509246526, 439930030199648
Offset: 1

Views

Author

R. H. Hardin Nov 07 2012

Keywords

Comments

Row 3 of A218842

Examples

			Some solutions for n=3
..1..0..1....0..0..1....0..0..1....1..0..0....1..1..1....1..0..0....1..0..1
..0..0..1....0..0..1....0..0..0....0..0..1....1..1..1....0..0..0....0..0..1
..0..0..1....0..0..1....0..0..0....1..1..1....1..0..0....0..1..1....0..0..0
		

A218845 Unmatched value maps: number of 4Xn binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 4Xn array.

Original entry on oeis.org

1, 65, 436, 3617, 26635, 201960, 1530846, 11617859, 88207678, 669575111, 5082650645, 38581655789, 292872656082, 2223190550341, 16876170296292, 128106451991984, 972451948238336, 7381852115978817, 56035406540101182
Offset: 1

Views

Author

R. H. Hardin Nov 07 2012

Keywords

Comments

Row 4 of A218842

Examples

			Some solutions for n=3
..0..0..1....1..0..0....1..0..0....1..0..0....1..1..0....0..0..1....1..1..0
..1..0..0....1..0..1....1..0..1....0..0..0....0..0..1....0..0..0....0..0..1
..0..1..1....1..0..0....0..0..1....0..0..1....1..0..0....1..0..0....1..0..0
..1..1..1....0..1..1....0..0..1....0..0..0....1..0..1....1..0..0....1..0..0
		

A218846 Unmatched value maps: number of 5Xn binary arrays indicating the locations of corresponding elements not equal to any horizontal or antidiagonal neighbor in a random 0..1 5Xn array.

Original entry on oeis.org

1, 200, 2043, 28888, 346501, 4299802, 53372068, 663615890, 8258480840, 102739744908, 1278038244556, 15897575084961, 197757402894222, 2460009603174968, 30601283457873781, 380663991433804098
Offset: 1

Views

Author

R. H. Hardin Nov 07 2012

Keywords

Comments

Row 5 of A218842

Examples

			Some solutions for n=3
..1..1..0....1..0..0....0..0..1....1..0..0....0..0..0....0..0..1....1..1..0
..0..0..1....0..1..1....0..0..0....1..0..1....1..0..0....1..1..1....0..0..1
..1..0..1....1..1..0....0..1..1....1..1..1....0..1..0....1..0..0....1..1..0
..0..0..1....0..0..1....1..0..1....1..0..1....0..0..1....0..1..0....0..0..0
..1..0..0....0..0..1....0..0..0....0..0..1....1..0..0....0..0..1....0..0..0
		
Showing 1-10 of 13 results. Next