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.

A268944 T(n,k)=Number of length-n 0..k arrays with no repeated value unequal to the previous repeated value plus one mod k+1.

Original entry on oeis.org

2, 3, 4, 4, 9, 6, 5, 16, 24, 10, 6, 25, 60, 63, 14, 7, 36, 120, 220, 159, 22, 8, 49, 210, 565, 788, 396, 30, 9, 64, 336, 1206, 2615, 2780, 969, 46, 10, 81, 504, 2275, 6834, 11950, 9684, 2349, 62, 11, 100, 720, 3928, 15239, 38322, 54045, 33404, 5640, 94, 12, 121, 990
Offset: 1

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Author

R. H. Hardin, Feb 16 2016

Keywords

Comments

Table starts
..2.....3......4.......5........6.........7.........8..........9.........10
..4.....9.....16......25.......36........49........64.........81........100
..6....24.....60.....120......210.......336.......504........720........990
.10....63....220.....565.....1206......2275......3928.......6345.......9730
.14...159....788....2615.....6834.....15239.....30344......55503......95030
.22...396...2780...11950....38322....101192....232696.....482490.....923150
.30...969...9684...54045...213042....667065...1773384....4171869....8925990
.46..2349..33404..242365..1175850...4370261..13443064...35904789...85953830
.62..5640.114292.1079240..6450402..28480312.101433800..307754712..824720230
.94.13455.388444.4777225.35200458.184750699.762265720.2628421029.7887767350

Examples

			Some solutions for n=6 k=4
..2. .4. .3. .1. .4. .4. .1. .2. .2. .0. .4. .2. .0. .3. .2. .3
..1. .4. .3. .0. .1. .0. .2. .3. .4. .0. .0. .1. .3. .0. .2. .3
..1. .2. .2. .1. .3. .4. .4. .0. .2. .2. .2. .2. .0. .2. .3. .1
..2. .4. .4. .3. .4. .0. .1. .2. .4. .1. .1. .3. .1. .0. .4. .2
..3. .0. .2. .0. .2. .1. .2. .3. .1. .0. .0. .0. .1. .3. .0. .0
..2. .3. .0. .0. .4. .4. .0. .4. .2. .2. .1. .2. .4. .3. .2. .4
		

Crossrefs

Column 1 is A027383.
Row 1 is A000027(n+1).
Row 2 is A000290(n+1).
Row 3 is A007531(n+2).

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) +a(n-2) -6*a(n-3)
k=3: a(n) = 5*a(n-1) -2*a(n-2) -12*a(n-3)
k=4: a(n) = 7*a(n-1) -7*a(n-2) -20*a(n-3)
k=5: a(n) = 9*a(n-1) -14*a(n-2) -30*a(n-3)
k=6: a(n) = 11*a(n-1) -23*a(n-2) -42*a(n-3)
k=7: a(n) = 13*a(n-1) -34*a(n-2) -56*a(n-3)
Empirical for row n:
n=1: a(n) = n + 1
n=2: a(n) = n^2 + 2*n + 1
n=3: a(n) = n^3 + 3*n^2 + 2*n
n=4: a(n) = n^4 + 4*n^3 + 3*n^2 + n + 1
n=5: a(n) = n^5 + 5*n^4 + 4*n^3 + 3*n^2 + 2*n - 1
n=6: a(n) = n^6 + 6*n^5 + 5*n^4 + 6*n^3 + 3*n^2 - n + 2
n=7: a(n) = n^7 + 7*n^6 + 6*n^5 + 10*n^4 + 4*n^3 + n^2 + 4*n - 3