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!.

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!.

A136594 Unsigned row sums of triangle A136590.

Original entry on oeis.org

1, 1, 2, 8, 26, 70, 820, 5152, 20316, 388712, 3666188, 17298908, 501805832, 6256792412, 33844737292, 1353617016078, 20960708128068, 137741948419428, 6588092586831028, 121860622573650906, 924837580461274556
Offset: 0

Views

Author

Paul D. Hanna, Jan 10 2008

Keywords

Comments

A136590 is the triangle of trinomial logarithmic coefficients.

Crossrefs

Programs

  • PARI
    a(n)=sum(k=0,n,n!/k!*abs(polcoeff(log(1+x+x^2 +x*O(x^n))^k,n)))
Showing 1-4 of 4 results.