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.

Previous Showing 21-30 of 30 results.

A061719 a(n) = Product_{k=0...n} (k!^3).

Original entry on oeis.org

1, 1, 8, 1728, 23887872, 41278242816000, 15407021574586368000000, 1972469516114225950359552000000000, 129292064547357027522197559428775936000000000000
Offset: 0

Views

Author

Jason Earls, Jun 20 2001

Keywords

Crossrefs

Cf. A000178.

Programs

  • Mathematica
    Table[Product[k!^3, {k, 0, n}], {n, 0, 10}] (* Vaclav Kotesovec, Nov 23 2023 *)
  • PARI
    for(n=0,11,print(prod(k=1,n,factorial(k)^3)))
    
  • PARI
    { for (n=0, 27, write("b061719.txt", n, " ", prod(k=2, n, k!^3)) ) } \\ Harry J. Smith, Jul 26 2009

Formula

a(n) = a(n-1)*A000442(n). - R. J. Mathar, Sep 26 2020
From Vaclav Kotesovec, Nov 23 2023: (Start)
a(n) = A000178(n)^3.
a(n) ~ (2*Pi)^(3*n/2 + 3/2) * n^(3*n^2/2 + 3*n + 5/4) / (A^3 * exp(9*n^2/4 + 3*n - 1/4)), where A is the Glaisher-Kinkelin constant A074962. (End)

Extensions

Terms corrected according to Jason Earls's instructions by Harry J. Smith, Jul 26 2009

A334394 Triangle read by rows: T(n,k) is the number of ordered triples of n-permutations with exactly k common descents, n>=0, 0<=k<=max(0,n-1).

Original entry on oeis.org

1, 1, 7, 1, 163, 52, 1, 8983, 4499, 341, 1, 966751, 660746, 98256, 2246, 1, 179781181, 155729277, 35677082, 2045282, 15177, 1, 53090086057, 55690144728, 17446464519, 1754605504, 42658239, 104952, 1, 23402291822743, 28825420903351, 11518335730323, 1717307782339, 84058424389, 905365701, 739153, 1
Offset: 0

Views

Author

Geoffrey Critzer, Apr 26 2020

Keywords

Comments

An ordered triple of n-permutations ( (a_1,a_2,...,a_n),(b_1,b_2,...,b_n),(c_1,c_2,...,c_n) ) has a common descent at position i, 1<=i<=n-1, if a_i > a_i+1, b_i > b_i+1 and c_i > c_i+1.

Examples

			Triangle begins:
       1;
       1;
       7,      1;
     163,     52,     1;
    8983,   4499,   341,   1;
  966751, 660746, 98256, 2246, 1;
  ...
		

References

  • R. P. Stanley, Enumerative Combinatorics, Volume I, Second Edition, example 3.18.3e, page 366.

Crossrefs

Cf. A192721, A008292, A212856 (column k=0), A000442 (row sums).

Programs

  • Maple
    T:= (n, k)-> n!^3*coeff(series(coeff(series((y-1)/(y-add((x*
        (y-1))^j/j!^3, j=0..n)), y, k+1), y, k), x, n+1), x, n):
    seq(seq(T(n,k), k=0..max(0, n-1)), n=0..10);  # Alois P. Heinz, Apr 28 2020
  • Mathematica
    nn = 6; e3[x_] := Sum[x^n/n!^3, {n, 0, nn}];Drop[Map[Select[#, # > 0 &] &,
       Table[n!^3, {n, 0, nn}] CoefficientList[Series[(y - 1)/(y - e3[x (y - 1)]), {x, 0, nn}], {x, y}]], 1] // Grid

Formula

Sum_{n>=0} Sum_{k>=0} T(n,k)*y^k*x^n/n!^3 = (y-1)/(y-f(x*(y-1))) where f(z) = Sum_{n>=0} z^n/n!^3.

A384044 a(n) = [x^n] Product_{k=1..n} (1 + k^3*x) / (1 - k^3*x).

Original entry on oeis.org

1, 2, 162, 75672, 104312000, 317309605650, 1803288012589602, 17180843554017736544, 254292459616733559570432, 5525508321588276184345621650, 168733575675064578625834983478850, 6994229599670887851052241626545021912, 382562895157136117988572795915676719695680
Offset: 0

Views

Author

Vaclav Kotesovec, May 18 2025

Keywords

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[(1+k^3*x)/(1-k^3*x), {k, 1, n}], {x, 0, n}], {n, 0, 12}]

Formula

a(n) ~ c * d^n * n!^3 / n^2, where d = 37.604795475701444958019770120055586495991039059348094619704... and c = 0.063895861310548119570865800164582089372152350471371583403...

A154226 List of pairs: {(n*(n+1)/2)^2, (n!)^3}.

Original entry on oeis.org

0, 1, 1, 1, 9, 8, 36, 216, 100, 13824, 225, 1728000, 441, 373248000, 784, 128024064000, 1296, 65548320768000, 2025, 47784725839872000, 3025, 47784725839872000000, 4356, 63601470092869632000000, 6084
Offset: 0

Views

Author

Roger L. Bagula, Jan 05 2009

Keywords

Crossrefs

Programs

  • Magma
    &cat[[(n*(n+1)/2)^2, Factorial(n)^3]: n in [0..15]]; // Vincenzo Librandi, Sep 07 2016
  • Mathematica
    a[0] = 0; a[n_] := a[n] = n^3 + a[n - 1];
    b[0] = 1; b[n_] := b[n] = n^3*b[n - 1];
    Flatten[Table[{a[n], b[n]}, {n, 0, 15}]]

Formula

a(2n+1) = A000442(n) = (n!)^3.
a(2n) = A000537(n) = (n*(n+1)/2)^2.

A287697 Triangle read by rows, (Sum_{k=0..n} T[n,k]*x^k) / (1-x)^(n+1) are generating functions of the columns of A287698.

Original entry on oeis.org

1, 0, 1, 0, 1, 7, 0, 1, 52, 163, 0, 1, 341, 4499, 8983, 0, 1, 2246, 98256, 660746, 966751, 0, 1, 15177, 2045282, 35677082, 155729277, 179781181, 0, 1, 104952, 42658239, 1754605504, 17446464519, 55690144728, 53090086057
Offset: 0

Views

Author

Peter Luschny, May 30 2017

Keywords

Examples

			Triangle starts:
0: [1]
1: [0, 1]
2: [0, 1,      7]
3: [0, 1,     52,      163]
4: [0, 1,    341,     4499,       8983]
5: [0, 1,   2246,    98256,     660746,      966751]
6: [0, 1,  15177,  2045282,   35677082,   155729277,   179781181]
7: [0, 1, 104952, 42658239, 1754605504, 17446464519, 55690144728, 53090086057]
...
Let q4(x) = (x + 341*x^2 + 4499*x^3 + 8983*x^4) / (1-x)^5 then the coefficients of the series expansion of q4 are column 4 of A287698.
		

Crossrefs

Programs

  • Maple
    A287697_row := n -> Delta(A287696_poly(n), n): # Delta defined in A287315.
    for n from 0 to 9 do A287697_row(n) od;
    A287697_eulerian := (n,x) -> add(A287697_row(n)[k+1]*x^k,k=0..n)/(1-x)^(n+1):
    for n from 0 to 4 do A287697_eulerian(n,x) od;

Formula

T(n,n) = A212856(n).
Sum_{k=0..n} T(n,k) = A000442(n).

A369698 AGM transform of positive cubes.

Original entry on oeis.org

0, 49, 40824, 96461056, 571250390625, 7338413252698641, 181953686508203782144, 7957561391610438862503936, 572547082070592542500791107625, 64157961305703333114506988525390625, 10714350425499230222239742740718898118656, 2571996060859292513876561308464753498396819456
Offset: 1

Views

Author

Paolo Xausa, Jan 29 2024

Keywords

Comments

See A368366 for the description of the AGM transform.

Crossrefs

Programs

  • Mathematica
    A369698[n_] := (n*(n+1)/2)^(2*n) - n^n*n!^3; Array[A369698, 15]
  • Python
    from math import factorial
    def A369698(n): return ((n*(n+1))**(m:=n<<1)>>m) - n**n*factorial(n)**3 # Chai Wah Wu, Jan 29 2024

Formula

a(n) = A000537(n)^n - A000312(n)*A000442(n).

A381160 a(n) is the permanent of the n X n matrix whose element (i,j) is equal to A008277(i+3, j) with 1 <= i,j <= n.

Original entry on oeis.org

1, 1, 22, 3206, 1902936, 3504528354, 16660734321540, 179059038168086056, 3938830136216956996632, 164125096331945477980176920, 12173562237817299484378342192768, 1527294306324982018922212102518520032, 310564445230567070838152555220146533261496, 98712056006032672983172826864304778359411112064
Offset: 0

Views

Author

Stefano Spezia, Feb 15 2025

Keywords

Examples

			a(3) = 3206:
  [1,  7,  6]
  [1, 15, 25]
  [1, 31, 90]
		

Crossrefs

Cf. A000442 (determinant), A008277, A381166.

Programs

  • Mathematica
    a[n_]:=Permanent[Table[StirlingS2[i+3,j],{i,n},{j,n}]]; Join[{1},Array[a,13]]
  • PARI
    a(n) = matpermanent(matrix(n, n, i, j, stirling(i+3,j,2))); \\ Michel Marcus, Feb 16 2025

A127488 a(n) = (n^2)!/(2*(n!)).

Original entry on oeis.org

6, 30240, 435891456000, 64630041847212441600000, 258328699159653623241666283438080000000
Offset: 2

Views

Author

Artur Jasinski, Jan 16 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(n^2)!/(2(n!)), {n, 2, 6}]

Formula

a(n) ~ n^(2*n^2 - n + 1/2) / (2 * exp(n*(n-1))). - Vaclav Kotesovec, Oct 26 2017

A380318 Product of the first n perfect powers (A001597).

Original entry on oeis.org

1, 1, 4, 32, 288, 4608, 115200, 3110400, 99532800, 3583180800, 175575859200, 11236854988800, 910185254092800, 91018525409280000, 11013241574522880000, 1376655196815360000000, 176211865192366080000000, 25374508587700715520000000, 4288291951321420922880000000, 840505222458998500884480000000, 181549128051143676191047680000000
Offset: 0

Views

Author

Ilya Gutkovskiy, Jan 20 2025

Keywords

Crossrefs

Programs

  • Mathematica
    Join[{1},FoldList[Times,Join[{1},Select[Range[250],GCD@@FactorInteger[#][[All,2]]>1&]]]] (* Harvey P. Dale, May 03 2025 *)

A386405 Decimal expansion of Product_{k>=0} (1 + 1/k!^3).

Original entry on oeis.org

4, 5, 2, 1, 1, 6, 2, 9, 8, 9, 7, 6, 8, 2, 1, 8, 4, 8, 1, 0, 2, 5, 3, 5, 9, 9, 3, 6, 0, 6, 2, 8, 3, 4, 8, 8, 6, 9, 7, 2, 4, 1, 5, 0, 1, 9, 8, 7, 1, 8, 8, 3, 1, 9, 2, 0, 7, 0, 8, 9, 9, 0, 9, 5, 5, 1, 6, 4, 3, 5, 0, 1, 5, 6, 2, 2, 5, 4, 5, 8, 2, 9, 4, 8, 0, 4, 2, 4, 9, 5, 6, 7, 6, 4, 3, 6, 6, 4, 5, 6, 9, 4, 1, 5, 6
Offset: 1

Views

Author

Kelvin Voskuijl, Aug 20 2025

Keywords

Examples

			4.52116298976821848102535993606283488697241501987188319...
		

Crossrefs

Programs

  • PARI
    prodinf(k=0, 1 + 1/k!^3)
Previous Showing 21-30 of 30 results.