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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A269776 T(n,k)=Number of length-n 0..k arrays with every repeated value unequal to the previous repeated value plus one mod k+1.

Original entry on oeis.org

2, 3, 4, 4, 9, 8, 5, 16, 27, 14, 6, 25, 64, 78, 24, 7, 36, 125, 252, 222, 40, 8, 49, 216, 620, 984, 624, 66, 9, 64, 343, 1290, 3060, 3816, 1740, 108, 10, 81, 512, 2394, 7680, 15040, 14724, 4824, 176, 11, 100, 729, 4088, 16674, 45600, 73680, 56592, 13320, 286, 12, 121
Offset: 1

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Author

R. H. Hardin, Mar 04 2016

Keywords

Comments

Table starts
...2.....3......4.......5........6.........7..........8..........9.........10
...4.....9.....16......25.......36........49.........64.........81........100
...8....27.....64.....125......216.......343........512........729.......1000
..14....78....252.....620.....1290......2394.......4088.......6552.......9990
..24...222....984....3060.....7680.....16674......32592......58824......99720
..40...624...3816...15040....45600....115920.....259504.....527616.....994680
..66..1740..14724...73680...270150....804636....2063880....4728384....9915210
.108..4824..56592..360000..1597500...5577768...16398144...42342912...98779500
.176.13320.216864.1755200..9432000..38621016..130175360..378929664..983566800
.286.36672.829116.8542720.55616250.267152256.1032602872.3389054976.9788946390

Examples

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

Crossrefs

Column 1 is A019274(n+2).
Column 2 is A269613.
Row 1 is A000027(n+1).
Row 2 is A000290(n+1).
Row 3 is A000578(n+1).
Row 4 is A058895(n+1).

Formula

Empirical for column k (apparently a(n) = 2*k*a(n-1) -k*(k-1)*a(n-2) -k^2*a(n-3)):
k=1: a(n) = 2*a(n-1) -a(n-3)
k=2: a(n) = 4*a(n-1) -2*a(n-2) -4*a(n-3)
k=3: a(n) = 6*a(n-1) -6*a(n-2) -9*a(n-3)
k=4: a(n) = 8*a(n-1) -12*a(n-2) -16*a(n-3)
k=5: a(n) = 10*a(n-1) -20*a(n-2) -25*a(n-3)
k=6: a(n) = 12*a(n-1) -30*a(n-2) -36*a(n-3)
k=7: a(n) = 14*a(n-1) -42*a(n-2) -49*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 + 3*n + 1
n=4: a(n) = n^4 + 4*n^3 + 6*n^2 + 3*n
n=5: a(n) = n^5 + 5*n^4 + 10*n^3 + 7*n^2 + n
n=6: a(n) = n^6 + 6*n^5 + 15*n^4 + 14*n^3 + 4*n^2
n=7: a(n) = n^7 + 7*n^6 + 21*n^5 + 25*n^4 + 11*n^3 + n^2
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