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.

A218663 T(n,k) = Hilltop maps: number of n X k binary arrays indicating the locations of corresponding elements not exceeded by any king-move neighbor in a random 0..1 n X k array.

Original entry on oeis.org

1, 3, 3, 5, 15, 5, 9, 57, 57, 9, 17, 225, 417, 225, 17, 31, 891, 3249, 3249, 891, 31, 57, 3519, 25533, 50625, 25533, 3519, 57, 105, 13905, 199489, 793881, 793881, 199489, 13905, 105, 193, 54945, 1560161, 12383361, 24879489, 12383361, 1560161, 54945
Offset: 1

Views

Author

R. H. Hardin, Nov 04 2012

Keywords

Comments

From Andrew Howroyd, May 10 2017: (Start)
Number of n X k binary matrices with every 1 adjacent to some 0 horizontally, vertically, diagonally or antidiagonally.
Number of dominating sets in the n X k king graph. (End)

Examples

			Table starts
....1........3...........5...............9.................17
....3.......15..........57.............225................891
....5.......57.........417............3249..............25533
....9......225........3249...........50625.............793881
...17......891.......25533..........793881...........24879489
...31.....3519......199489........12383361..........775176415
...57....13905.....1560161.......193349025........24176619049
..105....54945....12202673......3018953025.......754066017977
..193...217107....95434773.....47135449449.....23517838102321
..355...857871...746388537....735942652641....733484062428443
..653..3389769..5837454753..11490533873361..22876204302519509
.1201.13394241.45654295713.179405691966081.713472099034206097
...
Some solutions for n=3 k=4
..1..1..1..0....1..0..1..1....0..1..0..1....0..1..1..0....1..0..0..0
..0..1..0..0....0..0..0..0....1..0..0..1....0..0..1..1....0..0..1..1
..0..1..0..1....1..1..0..1....0..1..1..1....1..1..0..1....1..1..0..0
		

Crossrefs

Columns 1-7 are A000213(n+1), A218657, A218658, A218659, A218660, A218661, A218662.
Diagonal is A133791.

Formula

Empirical for column k:
k=1: a(n) = a(n-1) +a(n-2) +a(n-3)
k=2: a(n) = 3*a(n-1) +3*a(n-2) +3*a(n-3)
k=3: a(n) = 6*a(n-1) +11*a(n-2) +26*a(n-3) -5*a(n-4) -5*a(n-6)
k=4: a(n) = 12*a(n-1) +45*a(n-2) +180*a(n-3) -27*a(n-4) -81*a(n-6)
Columns k=1..z+1 for an underlying 0..z array: a(n) = sum(i=1..2z+1){(2^k-1)*a(n-i)} checked for z=1..3.

A218420 Hilltop maps: number of n X 2 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..1 n X 2 array.

Original entry on oeis.org

3, 13, 49, 191, 737, 2849, 11011, 42557, 164481, 635711, 2456993, 9496161, 36702211, 141852301, 548252401, 2118969471, 8189716289, 31652864193, 122336815619, 472825977597, 1827449929601, 7063007117695, 27298186799297, 105506194473793
Offset: 1

Views

Author

R. H. Hardin, Oct 28 2012

Keywords

Comments

Column 2 of A218426.

Examples

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

Crossrefs

Cf. A218426.

Formula

Empirical: a(n) = 3*a(n-1) + 3*a(n-2) + a(n-3) + a(n-4) + a(n-5).
Empirical g.f.: x*(3 + 4*x + x^2 + 2*x^3 + x^4) / (1 - 3*x - 3*x^2 - x^3 - x^4 - x^5). - Colin Barker, Mar 10 2018

A218419 Hilltop maps: number of n X n binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..1 n X n array.

Original entry on oeis.org

1, 13, 357, 41515, 19003811, 34328798853, 245489633250861, 6942897327251230265, 776657742366634012014603, 343639983448734808976866431015, 601395784904377113605427806277106571
Offset: 1

Views

Author

R. H. Hardin Oct 28 2012

Keywords

Comments

Diagonal of A218426

Examples

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

A218421 Hilltop maps: number of nX3 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..1 nX3 array.

Original entry on oeis.org

5, 49, 357, 2725, 20793, 158429, 1207525, 9203377, 70144889, 534620525, 4074695269, 31055936969, 236697756661, 1804029548133, 13749697742817, 104795505274517, 798715588594961, 6087537722095689, 46397135660186377
Offset: 1

Views

Author

R. H. Hardin Oct 28 2012

Keywords

Comments

Column 3 of A218426

Examples

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

Formula

Empirical: a(n) = 5*a(n-1) +16*a(n-2) +28*a(n-3) +17*a(n-4) +7*a(n-5) -3*a(n-6) +3*a(n-7) -8*a(n-8) -a(n-10) +a(n-11)

A218422 Hilltop maps: number of nX4 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..1 nX4 array.

Original entry on oeis.org

9, 191, 2725, 41515, 629659, 9539915, 144597047, 2191517757, 33214850067, 503408006597, 7629705089721, 115636627121941, 1752601092641329, 26562609636801375, 402585753260380041, 6101632743611966643
Offset: 1

Views

Author

R. H. Hardin Oct 28 2012

Keywords

Comments

Column 4 of A218426

Examples

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

Formula

Empirical: a(n) = 9*a(n-1) +72*a(n-2) +284*a(n-3) +526*a(n-4) +890*a(n-5) +902*a(n-6) +1382*a(n-7) -553*a(n-8) +2141*a(n-9) -1904*a(n-10) +416*a(n-11) -53*a(n-12) -263*a(n-13) -38*a(n-14) +38*a(n-15) -6*a(n-16) -18*a(n-17) +16*a(n-18) -a(n-20) +a(n-21)

A218423 Hilltop maps: number of nX5 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..1 nX5 array.

Original entry on oeis.org

17, 737, 20793, 629659, 19003811, 572765605, 17270172871, 520703946625, 15699497444771, 473348740584743, 14271727157207365, 430300515162577777, 12973799949967137925, 391167286570698841921, 11793911323529489973393
Offset: 1

Views

Author

R. H. Hardin Oct 28 2012

Keywords

Comments

Column 5 of A218426

Examples

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

A218424 Hilltop maps: number of nX6 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..1 nX6 array.

Original entry on oeis.org

31, 2849, 158429, 9539915, 572765605, 34328798853, 2058493362799, 123428176573409, 7400808508179025, 443756537313437079, 26607874601757021869, 1595422183998461122637, 95662355032495391763215
Offset: 1

Views

Author

R. H. Hardin Oct 28 2012

Keywords

Comments

Column 6 of A218426

Examples

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

A218425 Hilltop maps: number of nX7 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..1 nX7 array.

Original entry on oeis.org

57, 11011, 1207525, 144597047, 17270172871, 2058493362799, 245489633250861, 29274579482710357, 3490981608801331021, 416298960473587173025, 49643559085814354624329, 5919983699927241114279393
Offset: 1

Views

Author

R. H. Hardin Oct 28 2012

Keywords

Comments

Column 7 of A218426

Examples

			Some solutions for n=3
..0..1..0..1..0..1..1....0..1..1..1..1..0..0....0..1..0..1..0..1..1
..0..0..0..1..1..1..0....0..1..1..1..1..1..0....0..1..0..0..1..1..1
..0..1..1..1..1..0..1....0..0..0..1..1..0..1....0..0..1..0..1..0..0
		
Showing 1-8 of 8 results.