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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A268956 T(n,k)=Number of length-n 0..k arrays with no repeated value equal to the previous repeated value, with new values introduced in sequential order.

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 2, 4, 5, 1, 2, 4, 11, 7, 1, 2, 4, 12, 29, 11, 1, 2, 4, 12, 39, 77, 15, 1, 2, 4, 12, 40, 138, 201, 23, 1, 2, 4, 12, 40, 153, 499, 525, 31, 1, 2, 4, 12, 40, 154, 634, 1830, 1361, 47, 1, 2, 4, 12, 40, 154, 655, 2785, 6723, 3525, 63, 1, 2, 4, 12, 40, 154, 656, 3045
Offset: 1

Views

Author

R. H. Hardin, Feb 16 2016

Keywords

Comments

Table starts
..1....1.....1.....1.....1.....1.....1.....1.....1.....1.....1.....1.....1
..2....2.....2.....2.....2.....2.....2.....2.....2.....2.....2.....2.....2
..3....4.....4.....4.....4.....4.....4.....4.....4.....4.....4.....4.....4
..5...11....12....12....12....12....12....12....12....12....12....12....12
..7...29....39....40....40....40....40....40....40....40....40....40....40
.11...77...138...153...154...154...154...154...154...154...154...154...154
.15..201...499...634...655...656...656...656...656...656...656...656...656
.23..525..1830..2785..3045..3073..3074..3074..3074..3074..3074..3074..3074
.31.1361..6723.12634.15124.15579.15615.15616.15616.15616.15616.15616.15616
.47.3525.24714.58409.78930.84572.85314.85359.85360.85360.85360.85360.85360

Examples

			Some solutions for n=8 k=4
..0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0
..1. .1. .1. .0. .1. .1. .1. .1. .1. .1. .1. .1. .1. .1. .1. .1
..2. .2. .2. .1. .2. .2. .0. .1. .1. .2. .2. .2. .2. .0. .2. .2
..2. .3. .2. .0. .3. .3. .2. .2. .2. .1. .2. .3. .1. .1. .0. .1
..1. .4. .3. .2. .4. .2. .1. .3. .3. .3. .3. .1. .0. .2. .0. .3
..1. .3. .4. .1. .4. .2. .3. .0. .3. .3. .3. .4. .2. .1. .3. .4
..2. .2. .0. .2. .3. .4. .0. .1. .1. .1. .2. .0. .0. .2. .1. .2
..0. .0. .0. .3. .1. .1. .3. .2. .4. .3. .1. .0. .0. .1. .0. .2
		

Crossrefs

Column 1 is A052955(n-1).
Column 2 is A267912.
Column 3 is A268069.
Diagonal is A268010.

Formula

Empirical for column k:
k=1: a(n) = a(n-1) +2*a(n-2) -2*a(n-3)
k=2: a(n) = 3*a(n-1) +2*a(n-2) -8*a(n-3) for n>5
k=3: a(n) = 6*a(n-1) -3*a(n-2) -30*a(n-3) +28*a(n-4) +36*a(n-5) -36*a(n-6) for n>8
k=4: [order 9] for n>11
k=5: [order 12] for n>14
k=6: [order 15] for n>17
k=7: [order 18] for n>20

A268423 T(n,k)=Number of nXk 0..3 arrays with every repeated value in every row unequal to the previous repeated value, and in every column equal to the previous repeated value, and new values introduced in row-major sequential order.

Original entry on oeis.org

1, 2, 2, 4, 15, 5, 12, 159, 187, 14, 39, 2191, 9054, 2530, 44, 138, 30295, 494098, 467899, 34195, 147, 499, 421471, 25770278, 92967597, 22309009, 448667, 505, 1830, 5797959, 1339895662, 17282463434, 15615613747, 999810316, 5720450, 1750, 6723, 79367143
Offset: 1

Views

Author

R. H. Hardin, Feb 04 2016

Keywords

Comments

Table starts
....1.........2.............4..............12...............39..............138
....2........15...........159............2191............30295...........421471
....5.......187..........9054..........494098.........25770278.......1339895662
...14......2530........467899........92967597......17282463434....3197637400309
...44.....34195......22309009.....15615613747...10053286458091.6434348326690233
..147....448667.....999810316...2414369699870.5273786308929110
..505...5720450...42764566838.350815694801710
.1750..71224847.1764109373799
.6065.869969995

Examples

			Some solutions for n=3 k=4
..0..0..1..2....0..0..1..0....0..0..1..1....0..0..1..0....0..0..1..1
..1..1..3..1....1..0..2..1....2..2..3..2....2..2..1..3....2..2..0..2
..1..3..1..1....0..3..0..1....3..2..1..1....0..0..3..1....3..0..2..0
		

Crossrefs

Column 3 is A268047.
Row 1 is A268069.
Row 2 is A268070.
Row 3 is A268178.
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