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.

A089504 A generalization of triangle A071951 (Legendre-Stirling).

Original entry on oeis.org

1, 6, 1, 36, 30, 1, 216, 756, 90, 1, 1296, 18360, 6156, 210, 1, 7776, 441936, 387720, 31356, 420, 1, 46656, 10614240, 23705136, 4150440, 119556, 756, 1, 279936, 254788416, 1432922400, 521757936, 29257200, 373572, 1260, 1, 1679616
Offset: 1

Views

Author

Wolfdieter Lang, Dec 01 2003

Keywords

Comments

This triangle underlies the array entry A078741 ((3,3)-generalized Stirling2).
For the computation of the column sequences see A089505.

Examples

			[1]; [6,1]; [36,30,1]; [216,756,90,1]; ...
a(3,2) = 30 = ((-1)*(3*2*1)^1 + 4*(4*3*2)^1)/3.

Links

Crossrefs

Cf. A071951 (Legendre-Stirling, (2, 2) case).
The column sequences (without leading zeros) are A000400 (powers of 6), A089507, A089513-4, etc.
Cf. A008279, A089505, A089506.

Programs

  • Mathematica
    max = 10; f[m_] := 1/Product[1 - FactorialPower[r + 2, 3]*x, {r, 1, m}]; col[m_] := CoefficientList[f[m] + O[x]^(max - m + 1), x]; a[n_, m_] := col[m][[n - m + 1]]; Table[a[n, m], {n, 1, max}, {m, 1, n}] // Flatten (* Jean-François Alcover, Sep 01 2016 *)

Formula

G.f. for m-th column sequence (without leading zeros and m>=1) is 1/Product_{r=1..m} 1-fallfac(r+2, 3)*x with fallfac(n, k) := A008279(n, k) (falling factorials).
a(n, m) = Sum_{p=1..m} A089505(m, p)*((p+2)*(p+1)*p)^(n-m))/D(m) if n>=m>=1 else 0; with D(m) := A089506(m).

A089505 Triangle of signed numbers used for the computation of the column sequences of triangle A089504.

Original entry on oeis.org

1, -1, 4, 1, -24, 50, -1, 114, -950, 1350, 31, -15504, 400520, -1897200, 2052855, -9269, 19612560, -1431859000, 17333030000, -56265334125, 49236404224, 342953, -3011508588, 594221485000, -16634292228125, 123422029355625, -302409994743808, 222337901418633, -9945637
Offset: 1

Views

Author

Wolfdieter Lang, Dec 01 2003

Keywords

Comments

A089504(n+m,m)= sum(a(m,p)*((p+2)*(p+1)*p)^n,p=1..m)/D(m) with D(m) := A089506(m); m=1,2,..., n>=0.

Examples

			[1]; [ -1,4]; [1,-24,50]; [ -1,114,-950,1350]; ...
a(3,2)= -24 = 27*(-1)*((4*3*2)^2)/((4*3*2-3*2*1)*(5*4*3-4*3*2)).
A089504(2+3,3) = A089513(2) = 6156 = (1*(3*2*1)^2 - 24*(4*3*2)^2 + 50*(5*4*3)^2)/27.

Links

Crossrefs

Companion denominator sequence is A089506.

Programs

  • Mathematica
    b[n_, m_] := (-1)^(n - m)*FactorialPower[m + 2, 3]^(n - 1)/(Product[ FactorialPower[m + 2, 3] - FactorialPower[r + 2, 3], {r, 1, m - 1}] * Product[ FactorialPower[r + 2, 3] - FactorialPower[m + 2, 3], {r, m + 1, n}]); den[n_] := LCM @@ Table[ Denominator[b[n, m]], {m, 1, n}]; a[n_, m_] := den[n]*b[n, m]; Table[a[n, m], {n, 1, 10}, {m, 1, n}] // Flatten (* Jean-François Alcover, Sep 02 2016 *)

Formula

a(n, m)= D(n)*((-1)^(n-m))*(((m+2)*(m+1)*m)^(n-1))/(product(fallfac(m+2, 3)-fallfac(r+2, 3), r=1..m-1)*product(fallfac(r+2, 3)-fallfac(m+2, 3), r=m+1..n)), with D(n) := A089506(n) and fallfac(n, m) := A008279(n, m) (falling factorials), 1<=m<=n else 0. (Replace in the denominator the first product by 1 if m=1 and the second one by 1 if m=n.)
a(n, m)= A089506(n)*((-1)^(n-m))*(fallfac(m+2, 3)^(n-1))*(3*m^2+6*m+2)/((n-m)!*(m-1)!*product(fallfac(m+r+2, 2)-r*m, r=1..n)), n>=m>=1.

A089507 Second column of triangle A089504 and second column of array A078741 divided by 18.

Original entry on oeis.org

1, 30, 756, 18360, 441936, 10614240, 254788416, 6115201920, 146766525696, 3522406694400, 84537821131776, 2028908069959680, 48693795855814656, 1168651113600245760, 28047626804770062336, 673143043784666480640
Offset: 0

Views

Author

Wolfdieter Lang, Dec 01 2003

Keywords

Comments

Convolution of A000400 (powers of 6) with A009968 (powers of 24).

Links

Crossrefs

Cf. A089505, A089513, A089514.

Programs

  • Magma
    [6^n*(4^(n+1)-1)/3: n in [0..15]]; // Vincenzo Librandi, Oct 18 2017
  • Mathematica
    CoefficientList[Series[1/((1-6x)(1-24x)),{x,0,20}],x] (* or *) LinearRecurrence[{30,-144},{1,30},20] (* Harvey P. Dale, Sep 25 2017 *)

Formula

G.f.: 1/((1-3*2*1*x)*(1-4*3*2*x)).
a(n) = A089504(n+2, 2), n>=0.
a(n) = (4*(4*3*2)^n - (3*2*1)^n)/3 = (2^n)*(2^(2*(n+1))-1)*3^(n-1).
a(n) = 6^n*(4^(n+1)-1)/3. - Vincenzo Librandi, Oct 18 2017

A089514 Fourth column of triangle A089504.

Original entry on oeis.org

1, 210, 31356, 4150440, 521757936, 64043874720, 7771495098816, 937759335004800, 112842062355914496, 13559707534436743680, 1628284591773850622976, 195461334300256627599360
Offset: 0

Views

Author

Wolfdieter Lang, Dec 01 2003

Keywords

Comments

Convolution of A089513 with powers of 120.

Links

Crossrefs

Cf. A089505, A089513.

Programs

  • Mathematica
    CoefficientList[Series[1/((1-6x)(1-24x)(1-60x)(1-120x)),{x,0,20}],x] (* or *) LinearRecurrence[ {210,-12744,241920,-1036800},{1,210,31356,4150440},20] (* Harvey P. Dale, Mar 17 2023 *)

Formula

G.f.: 1/((1-3*2*1*x)*(1-4*3*2*x)*(1-5*4*3*x)*(1-6*5*4*x)).
a(n) = A089504(n+4, 4), n>=0.
a(n) = (1350*(6*5*4)^n - 950*(5*4*3)^n + 114*(4*3*2)^n - (3*2*1)^n)/513.

A089518 Third column (k=5) of array A078741 ((3,3)-Stirling2) divided by 9.

Original entry on oeis.org

1, 138, 10476, 683208, 42315696, 2570768928, 155010407616, 9318969502848, 559578466388736, 33585275183251968, 2015370124337581056, 120928294183739148288, 7255843732407562776576, 435354129897768445943808
Offset: 0

Views

Author

Wolfdieter Lang, Dec 01 2003

Keywords

References

  • P. Blasiak, K. A. Penson and A. I. Solomon, The general boson normal ordering problem, Phys. Lett. A 309 (2003) 198-205.

Links

Crossrefs

Cf. A089513 (third column of A089504), A089519, A090219.

Formula

G.f.: (1+48*x)/((1-3*2*1*x)*(1-4*3*2*x)*(1-5*4*3*x)).
a(n)= (10*(5*4*3)^n - 8*(4*3*2)^n + (3*2*1)^n)/3 = b(n) + 48*b(n-1), with b(n) := A089513(n).
Showing 1-5 of 5 results.

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