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 1-5 of 5 results.

A229637 T(n,k) = number of defective 3-colorings of an n X k 0..2 array connected horizontally, diagonally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.

Original entry on oeis.org

0, 0, 0, 1, 6, 0, 3, 40, 39, 0, 12, 122, 244, 202, 0, 40, 488, 1109, 1496, 925, 0, 120, 1608, 6031, 10227, 8800, 3924, 0, 336, 5392, 28448, 77620, 89331, 50084, 15795, 0, 896, 17368, 136778, 535671, 960325, 747299, 277996, 61182, 0, 2304, 55232, 633328
Offset: 1

Views

Author

R. H. Hardin, Sep 27 2013

Keywords

Comments

Table starts
.0.....0.......1........3.........12..........40...........120............336
.0.....6......40......122........488........1608..........5392..........17368
.0....39.....244.....1109.......6031.......28448........136778.........633328
.0...202....1496....10227......77620......535671.......3723370.......25022190
.0...925....8800....89331.....960325.....9722206......98015235......960209886
.0..3924...50084...747299...11485716...170405645....2495874984....35693194243
.0.15795..277996..6049298..133784624..2902520386...61836040854..1290897457785
.0.61182.1513104.47723226.1525870912.48303362606.1498317588826.45634751291449

Examples

			Some solutions for n=3, k=4:
  0 1 0 2     0 1 0 1     0 1 0 2     0 1 0 0     0 1 1 2
  2 1 0 2     2 1 0 1     2 2 0 1     0 2 1 2     0 1 0 2
  2 1 2 0     1 2 0 1     1 1 0 1     0 2 1 0     0 1 0 1
		

Crossrefs

Column 2 is A229600.
Row 1 is A052482(n-2).

Formula

Empirical for column k:
k=1: a(n) = a(n-1)
k=2: a(n) = 9*a(n-1) - 27*a(n-2) + 27*a(n-3) for n > 5
k=3: a(n) = 15*a(n-1) - 81*a(n-2) + 185*a(n-3) - 162*a(n-4) + 60*a(n-5) - 8*a(n-6) for n > 7.
k=4: [order 6] for n > 9.
k=5: [order 18] for n > 20.
k=6: [order 27] for n > 30.
k=7: [order 57] for n > 60.
Empirical for row n:
n=1: a(n) = 6*a(n-1) - 12*a(n-2) + 8*a(n-3) for n > 6.
n=2: a(n) = 6*a(n-1) - 6*a(n-2) - 16*a(n-3) + 12*a(n-4) + 24*a(n-5) + 8*a(n-6).
n=3: [order 9] for n > 12.
n=4: [order 18] for n > 21.
n=5: [order 30] for n > 33.
n=6: [order 69] for n > 72.

A229694 T(n,k) = number of defective 3-colorings of an n X k 0..2 array connected horizontally and antidiagonally with exactly two mistakes, and colors introduced in row-major 0..2 order.

Original entry on oeis.org

0, 0, 0, 1, 3, 0, 3, 43, 40, 0, 12, 245, 626, 336, 0, 40, 1171, 5077, 6732, 2304, 0, 120, 5077, 35825, 80757, 62856, 14080, 0, 336, 20691, 230383, 848937, 1125333, 539568, 79872, 0, 896, 80757, 1400413, 8186713, 17724789, 14461173, 4377888, 430080, 0
Offset: 1

Views

Author

R. H. Hardin, Sep 27 2013

Keywords

Examples

			Some solutions for n=3, k=4:
  0 1 2 1     0 1 0 2     0 1 0 2     0 0 1 2     0 1 0 2
  0 1 0 2     0 2 0 2     0 2 1 0     1 0 0 1     0 2 1 1
  1 2 1 1     2 1 2 0     2 2 1 2     2 1 2 0     1 0 2 2
Table starts
.0......0........1..........3...........12............40.............120
.0......3.......43........245.........1171..........5077...........20691
.0.....40......626.......5077........35825........230383.........1400413
.0....336.....6732......80757.......848937.......8186713........75035643
.0...2304....62856....1125333.....17724789.....258006388......3583403667
.0..14080...539568...14461173....342532665....7551515197....159377253183
.0..79872..4377888..175867605...6279934941..210095323918...6749642728251
.0.430080.34105536.2054728053.110801828529.5632122625852.275739382892979
		

Crossrefs

Column 2 is A002700(n+1).
Row 1 is A052482(n-2).

Formula

Empirical for column k:
k=1: a(n) = a(n-1).
k=2: a(n) = 12*a(n-1) - 48*a(n-2) + 64*a(n-3).
k=3: a(n) = 18*a(n-1) - 108*a(n-2) + 216*a(n-3) for n > 4.
k=4: a(n) = 27*a(n-1) - 243*a(n-2) + 729*a(n-3) for n > 4.
k=5: [order 6] for n > 7.
k=6: [order 9] for n > 11.
k=7: [order 12] for n > 14.
Empirical for row n:
n=1: a(n) = 6*a(n-1) - 12*a(n-2) + 8*a(n-3) for n > 6.
n=2: a(n) = 9*a(n-1) - 27*a(n-2) + 27*a(n-3) for n > 6.
n=3: a(n) = 15*a(n-1) - 81*a(n-2) + 185*a(n-3) - 162*a(n-4) + 60*a(n-5) - 8*a(n-6) for n > 10.
n=4: [order 9] for n > 17.
n=5: [order 21] for n > 27.
n=6: [order 29] for n > 39.
n=7: [order 86] for n > 94.

A080929 Sequence associated with a(n) = 2*a(n-1) + k*(k+2)*a(n-2).

Original entry on oeis.org

1, 3, 12, 40, 120, 336, 896, 2304, 5760, 14080, 33792, 79872, 186368, 430080, 983040, 2228224, 5013504, 11206656, 24903680, 55050240, 121110528, 265289728, 578813952, 1258291200, 2726297600, 5888802816, 12683575296, 27246198784
Offset: 0

Views

Author

Paul Barry, Feb 26 2003

Keywords

Comments

The third column of number triangle A080928.

Crossrefs

Essentially the same as A052482.

Programs

  • GAP
    Concatenation([1], List([1..30], n-> 2^(n-1)*Binomial(n+2,2))); # G. C. Greubel, Jul 23 2019
  • Magma
    [n eq 0 select 1 else (n+1)*(n+2)*2^(n-2): n in [0..30]]; // Vincenzo Librandi, Sep 22 2011
    
  • Maple
    [seq (ceil(binomial(n+2,2)*2^(n-1)),n=0..30)]; # Zerinvary Lajos, Nov 01 2006
  • Mathematica
    CoefficientList[Series[(1-x)(1-2x+4x^2)/(1-2x)^3, {x,0,30}], x] (* Michael De Vlieger, Sep 21 2017 *)
    Join[{1}, LinearRecurrence[{6,-12,8}, {3,12,40}, 30]] (* G. C. Greubel, Jul 23 2019 *)
  • PARI
    vector(30, n, n--; if(n==0,1, 2^(n-1)*binomial(n+2,2) )) \\ G. C. Greubel, Jul 23 2019
    
  • Sage
    [1]+[2^(n-1)*binomial(n+2,2) for n in (1..30)] # G. C. Greubel, Jul 23 2019
    

Formula

G.f.: (1-x)*(1-2*x+4*x^2)/(1-2*x)^3.
For n>0, a(n) = (n+1)*(n+2)*2^(n-2). - Ralf Stephan, Jan 16 2004
a(n) = Sum_{k=0..n} Sum_{i=0..n} (k+1)*binomial(n-1,i). - Wesley Ivan Hurt, Sep 20 2017
From Amiram Eldar, Jan 07 2022: (Start)
Sum_{n>=0} 1/a(n) = 7 - 8*log(2).
Sum_{n>=0} (-1)^n/a(n) = 24*log(3/2) - 9. (End)

A229606 T(n,k) = number of defective 3-colorings of an n X k 0..2 array connected horizontally and vertically with exactly two mistakes, and colors introduced in row-major 0..2 order.

Original entry on oeis.org

0, 0, 0, 1, 6, 1, 3, 39, 39, 3, 12, 202, 396, 202, 12, 40, 925, 3040, 3040, 925, 40, 120, 3924, 20714, 35182, 20714, 3924, 120, 336, 15795, 131345, 362100, 362100, 131345, 15795, 336, 896, 61182, 792929, 3476928, 5655616, 3476928, 792929, 61182, 896
Offset: 1

Views

Author

R. H. Hardin, Sep 26 2013

Keywords

Comments

Table starts
...0.....0.......1.........3..........12...........40............120
...0.....6......39.......202.........925.........3924..........15795
...1....39.....396......3040.......20714.......131345.........792929
...3...202....3040.....35182......362100......3476928.......31848813
..12...925...20714....362100.....5655616.....82613904.....1153135492
..40..3924..131345...3476928....82613904...1840258874....39229935270
.120.15795..792929..31848813..1153135492..39229935270..1279020266434
.336.61182.4618048.281845934.15568071652.809714005005.40413033646242

Examples

			Some solutions for n=3, k=4:
  0 1 1 2     0 1 0 1     0 1 2 1     0 1 2 1     0 1 2 0
  2 0 0 1     1 2 1 2     1 2 1 1     2 0 1 2     1 0 2 1
  0 2 1 2     0 2 0 0     0 1 0 2     0 0 2 0     1 2 0 2
		

Crossrefs

Column 1 is A052482(n-2).

Formula

Empirical for column k:
k=1: a(n) = 6*a(n-1) - 12*a(n-2) + 8*a(n-3) for n > 6.
k=2: a(n) = 9*a(n-1) - 27*a(n-2) + 27*a(n-3) for n > 5.
k=3: a(n) = 15*a(n-1) - 81*a(n-2) + 185*a(n-3) - 162*a(n-4) + 60*a(n-5) - 8*a(n-6) for n > 7.
k=4: [order 9] for n > 11.
k=5: [order 16] for n > 17.
k=6: [order 21] for n > 23.
k=7: [order 46] for n > 47.

A301459 Number of 6-cycles in the n-folded cube graph.

Original entry on oeis.org

0, 0, 96, 320, 3200, 4480, 14336, 43008, 122880, 337920, 901120, 2342912, 5963776, 14909440, 36700160, 89128960, 213909504, 508035072, 1195376640, 2789212160, 6459228160, 14856224768, 33957085184
Offset: 2

Views

Author

Eric W. Weisstein, Mar 21 2018

Keywords

Comments

a(5) is also the number of 6-cycles in the 2-Keller graph.

Crossrefs

Cf. A052482 (4-cycles).

Programs

  • Mathematica
    Table[Piecewise[{{0, n == 3}, {96, n == 4}, {3200, n == 6}}, 2^(n - 1) n (n - 1) (n - 2)/3], {n, 2, 20}]
    Join[{0, 0, 96, 320, 3200}, LinearRecurrence[{8, -24, 32, -16}, {4480, 14336, 43008, 122880, 337920}, 14]]
    CoefficientList[Series[32 x^2 (3 - 14 x + 92 x^2 - 516 x^3 + 1456 x^4 - 1920 x^5 + 960 x^6)/(-1 + 2 x)^4, {x, 0, 20}], x]

Formula

a(n) = 2^(n - 1)*n*(n - 1)*(n - 2)/3 for n > 6.
a(n) = 8*a(n-1) - 24*a(n-2) + 32*a(n-3) - 16*a(n-4) for n > 10.
G.f.: 32*x^4*(3 - 14*x + 92*x^2 - 516*x^3 + 1456*x^4 - 1920*x^5 + 960*x^6)/(-1 + 2*x)^4.
Showing 1-5 of 5 results.