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 1-9 of 9 results.

A184368 1/3 the number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having at least two equal elements connected horizontally or vertically.

Original entry on oeis.org

21, 153, 1107, 8019, 58077, 420633, 3046491, 22064643, 159806277, 1157419449, 8382773187, 60713414163, 439725443661, 3184773389433, 23066169329547, 167059976482179, 1209955382858997, 8763272085493593, 63469230958692531
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2011

Keywords

Comments

Column 1 of A184376.

Examples

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

Crossrefs

Cf. A184376.

Formula

Empirical: a(n) = 6*a(n-1) + 9*a(n-2).
Conjectures from Colin Barker, Feb 27 2018: (Start)
G.f.: 3*x*(7 + 9*x) / (1 - 6*x - 9*x^2).
a(n) = ((3-3*sqrt(2))^n*(-4+3*sqrt(2)) + (3*(1+sqrt(2)))^n*(4+3*sqrt(2))) / (2*sqrt(2)).
(End)

A184369 1/3 the number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock having at least two equal elements connected horizontally or vertically.

Original entry on oeis.org

153, 2755, 49235, 880781, 15754461, 281803871, 5040682279, 90163722073, 1612776998193, 28848073268443, 516011408652059, 9230001997285733, 165098940527912805, 2953158641948611223, 52823754874667184367
Offset: 1

Views

Author

R. H. Hardin, Jan 12 2011

Keywords

Comments

Column 2 of A184376.

Examples

			Some solutions for 5 X 3 with a(1,1)=0:
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0
..1..0..2....1..2..2....0..1..0....0..2..2....1..1..1....0..2..0....1..1..0
..1..2..2....0..2..0....1..1..1....1..1..2....1..2..0....1..2..0....1..0..0
..1..2..2....1..1..0....2..1..2....2..1..2....1..1..1....1..2..0....2..2..2
..1..1..1....2..2..2....0..1..0....0..0..0....0..2..0....0..2..1....0..2..0
		

Crossrefs

Cf. A184376.

Formula

Empirical: a(n) = 17*a(n-1) + 19*a(n-2) - 57*a(n-3) + 18*a(n-4).
Empirical g.f.: x*(153 + 154*x - 507*x^2 + 162*x^3) / (1 - 17*x - 19*x^2 + 57*x^3 - 18*x^4). - Colin Barker, Feb 27 2018

A184370 1/3 the number of (n+1)X4 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

Original entry on oeis.org

1107, 49235, 2167173, 95528423, 4210059673, 185547841629, 8177524177277, 360402692568245, 15883791500540967, 700035935394350709, 30852225032929689819, 1359729896274471875219, 59926484677950059719491
Offset: 1

Views

Author

R. H. Hardin Jan 12 2011

Keywords

Comments

Column 3 of A184376

Examples

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

Formula

Empirical: a(n)=38*a(n-1)+302*a(n-2)-1368*a(n-3)-6770*a(n-4)+12666*a(n-5)-575*a(n-6)-5790*a(n-7)+828*a(n-8)+648*a(n-9)

A184371 1/3 the number of (n+1) X 5 0..2 arrays with every 2 X 2 subblock having at least two equal elements connected horizontally or vertically.

Original entry on oeis.org

8019, 880781, 95528423, 10378244309, 1127256514575, 122443114867993, 13299774554091575, 1444622701339019869, 156915034606615850427, 17044123945719790186817, 1851334139596041020316331
Offset: 1

Views

Author

R. H. Hardin Jan 12 2011

Keywords

Comments

Column 4 of A184376.

Examples

			Some solutions for 3 X 5 with a(1,1)=0
..0..0..0..1..0....0..0..0..1..1....0..0..0..0..0....0..0..0..0..0
..1..2..2..2..0....0..0..2..2..1....0..1..0..1..1....2..2..0..1..2
..1..1..1..1..1....2..1..1..0..0....2..1..0..0..0....0..2..0..1..0
		

Crossrefs

Cf. A184376.

Formula

Empirical: a(n)=114*a(n-1)-197*a(n-2)-44924*a(n-3)+280944*a(n-4)+3429792*a(n-5)-38126443*a(n-6)+98209829*a(n-7)+162477726*a(n-8)-1059045499*a(n-9)+651177189*a(n-10)+3269771125*a(n-11)-4412158618*a(n-12)-3526224683*a(n-13)+7595898885*a(n-14)+727564626*a(n-15)-4875456557*a(n-16)+367654226*a(n-17)+1090025544*a(n-18)-17907882*a(n-19)-56592728*a(n-20)+3381324*a(n-21)+616392*a(n-22)-47520*a(n-23).

A184372 1/3 the number of (n+1)X6 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

Original entry on oeis.org

58077, 15754461, 4210059673, 1127256514575, 301753233626727, 80778452206783159, 21624059735461675335, 5788675585887326994869, 1549605510397241533259837, 414823258633731476239250435
Offset: 1

Views

Author

R. H. Hardin Jan 12 2011

Keywords

Comments

Column 5 of A184376

Examples

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

A184373 1/3 the number of (n+1)X7 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

Original entry on oeis.org

420633, 281803871, 185547841629, 122443114867993, 80778452206783159, 53293289955084658949, 35159890626610196979641, 23196517518911246631354055, 15303755709562804997482560737, 10096556166552290137769922123373
Offset: 1

Views

Author

R. H. Hardin Jan 12 2011

Keywords

Comments

Column 6 of A184376

Examples

			Some solutions for 3X7 with a(1,1)=0
..0..0..0..0..0..0..0....0..0..0..0..0..0..0....0..0..0..0..0..0..0
..1..2..2..0..0..0..0....1..1..2..0..0..0..1....1..1..0..0..0..0..1
..1..1..2..0..2..0..0....0..0..2..0..2..0..0....0..1..0..1..0..2..1
		

A184374 1/3 the number of (n+1)X8 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

Original entry on oeis.org

3046491, 5040682279, 8177524177277, 13299774554091575, 21624059735461675335, 35159890626610196979641, 57168347029530545962203193, 92953139774330929595592449437, 151137575901032303453595440035363
Offset: 1

Views

Author

R. H. Hardin Jan 12 2011

Keywords

Comments

Column 7 of A184376

Examples

			Some solutions for 3X8 with a(1,1)=0
..0..0..0..0..1..1..2..1....0..0..0..0..0..0..1..0....0..0..0..0..2..0..2..1
..0..0..0..0..0..1..2..0....0..0..0..0..2..2..2..0....0..0..0..0..1..1..1..1
..0..0..0..0..0..0..0..0....0..0..0..0..2..0..1..1....0..0..0..0..0..0..0..2
		

A184375 1/3 the number of (n+1)X9 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

Original entry on oeis.org

22064643, 90163722073, 360402692568245, 1444622701339019869, 5788675585887326994869, 23196517518911246631354055, 92953139774330929595592449437, 372482322079037724494019844619359
Offset: 1

Views

Author

R. H. Hardin Jan 12 2011

Keywords

Comments

Column 8 of A184376

Examples

			Some solutions for 3X9 with a(1,1)=0
..0..0..0..0..0..1..2..2..2....0..0..0..0..0..0..0..0..2
..0..0..0..0..0..0..2..2..2....0..0..0..0..0..2..1..0..1
..0..0..0..0..0..1..2..2..0....0..0..0..0..0..1..1..0..2
		

A184367 1/3 the number of (n+1)X(n+1) 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

Original entry on oeis.org

21, 2755, 2167173, 10378244309, 301753233626727, 53293289955084658949, 57168347029530545962203193, 372482322079037724494019844619359
Offset: 1

Views

Author

R. H. Hardin Jan 12 2011

Keywords

Comments

Diagonal of A184376

Examples

			Some solutions for 3X3 with a(1,1)=0
..0..1..2....0..2..1....0..0..2....0..0..2....0..0..1....0..2..1....0..1..0
..2..1..1....1..1..1....2..2..2....0..0..2....2..0..2....0..0..1....0..1..2
..1..1..2....0..1..1....0..1..0....1..1..2....2..0..0....0..2..1....2..1..1
		
Showing 1-9 of 9 results.