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 1-4 of 4 results.

A136590 Triangle of trinomial logarithmic coefficients: A027907(n,k) = Sum_{i=0..k} T(k,i)*n^i/k!.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, -4, 3, 1, 0, 6, -13, 6, 1, 0, 24, -10, -25, 10, 1, 0, -240, 394, -135, -35, 15, 1, 0, 720, -2016, 1834, -525, -35, 21, 1, 0, 5040, -5076, -3668, 5089, -1400, -14, 28, 1, 0, -80640, 170064, -110692, 14364, 9849, -3024, 42, 36, 1, 0, 362880, -1155024, 1339020, -672400, 118125, 12873, -5670, 150, 45, 1
Offset: 0

Views

Author

Paul D. Hanna, Jan 10 2008

Keywords

Comments

A027907 is the triangle of trinomial coefficients.
The Bell transform of A136591(n+1). For the definition of the Bell transform see A264428. - Peter Luschny, Jan 18 2016

Examples

			Triangle begins:
1;
0, 1;
0, 1, 1;
0, -4, 3, 1;
0, 6, -13, 6, 1;
0, 24, -10, -25, 10, 1;
0, -240, 394, -135, -35, 15, 1;
0, 720, -2016, 1834, -525, -35, 21, 1;
0, 5040, -5076, -3668, 5089, -1400, -14, 28, 1;
0, -80640, 170064, -110692, 14364, 9849, -3024, 42, 36, 1;
0, 362880, -1155024, 1339020, -672400, 118125, 12873, -5670, 150, 45, 1; ...
Trinomial coefficients can be calculated as illustrated by:
A027907(4,3) = (T(3,0)*4^0 + T(3,1)*4^1 + T(3,2)*4^2 + T(3,3)*4^3)/3! =
(0 - 4*4 + 3*4^2 + 1*4^3)/3! = 96/6 = 16.
		

Crossrefs

Cf. columns: A136591, A136592, A136593; A136594 (unsigned row sums); A136595 (matrix inverse); A027907, A002426.

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    BellMatrix(n -> n!*(modp(n+1,3)-modp(n,3)), 9); # Peter Luschny, Jan 27 2016
  • Mathematica
    BellMatrix[f_Function, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]];
    rows = 11;
    M = BellMatrix[#!*(Mod[# + 1, 3] - Mod[#, 3])&, rows];
    Table[M[[n, k]], {n, 1, rows}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jun 23 2018, after Peter Luschny *)
  • PARI
    {T(n,k)=n!/k!*polcoeff(log(1+x+x^2 +x*O(x^n))^k,n)}
    for(n=0,10, for(k=0,n, print1( T(n,k),", "));print(""))
    
  • Sage
    # uses[bell_matrix from A264428]
    bell_matrix(lambda n: A136591(n+1), 10) # Peter Luschny, Jan 18 2016

Formula

E.g.f. of column k = log(1 + x + x^2)^k / k! for k>=0.
Central trinomial coefficients: A002426(n) = Sum_{k=0..n} T(n,k)*n^k/n!.

A136591 Column 1 of triangle A136590.

Original entry on oeis.org

1, 1, -4, 6, 24, -240, 720, 5040, -80640, 362880, 3628800, -79833600, 479001600, 6227020800, -174356582400, 1307674368000, 20922789888000, -711374856192000, 6402373705728000, 121645100408832000, -4865804016353280000, 51090942171709440000
Offset: 1

Views

Author

Paul D. Hanna, Jan 10 2008

Keywords

Crossrefs

Programs

  • PARI
    {a(n) = n!*polcoeff( log(1+x+x^2 +x*O(x^(n+1))),n)}
    for(n=1,30,print1(a(n),", "))

Formula

E.g.f.: log(1 + x + x^2).
a(n) = n!*A061347(n) for n>=1.

A136592 Column 2 of triangle A136590.

Original entry on oeis.org

1, 3, -13, -10, 394, -2016, -5076, 170064, -1155024, -5005440, 193724640, -1656720000, -10280355840, 465087087360, -4804977542400, -39012996556800, 2035558551398400, -24660231399014400, -248246498826547200, 14713557956794368000
Offset: 2

Views

Author

Paul D. Hanna, Jan 10 2008

Keywords

Examples

			E.g.f.: A(x) = 1*x^2/2! + 3*x^3/3! - 13*x^4/4! - 10*x^5/5! + 394*x^6/6! +...
		

Crossrefs

Programs

  • Mathematica
    With[{nn=30},Drop[CoefficientList[Series[Log[1+x+x^2]^2/2,{x,0,nn}],x] Range[ 0,nn]!,2]] (* Harvey P. Dale, Feb 28 2013 *)
  • PARI
    a(n)=(n+2)!*polcoeff(log(1+x+x^2 +x*O(x^(n+2)))^2/2!,n+2)

Formula

E.g.f.: A(x) = log(1 + x + x^2)^2 / 2!.

A136593 Column 3 of triangle A136590.

Original entry on oeis.org

1, 6, -25, -135, 1834, -3668, -110692, 1339020, -1181664, -164709864, 2206092096, 395662176, -463716547776, 7029335571840, 8900411569920, -2265668505227520, 38689597829053440, 92447263589921280, -17785648201625856000, 338957966532455424000
Offset: 3

Views

Author

Paul D. Hanna, Jan 10 2008

Keywords

Examples

			E.g.f.: A(x) = 1*x^3/3! + 6*x^4/4! - 25*x^5/5! - 135*x^6/6! + 1834*x^7/7! -...
		

Crossrefs

Programs

  • PARI
    a(n)=(n+3)!*polcoeff(log(1+x+x^2 +x*O(x^(n+3)))^3/3!,n+3)

Formula

E.g.f.: A(x) = log(1 + x + x^2)^3 / 3!.
Showing 1-4 of 4 results.