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 1-6 of 6 results.

A136595 Matrix inverse of triangle A136590.

Original entry on oeis.org

1, 0, 1, 0, -1, 1, 0, 7, -3, 1, 0, -61, 31, -6, 1, 0, 751, -375, 85, -10, 1, 0, -11821, 5911, -1350, 185, -15, 1, 0, 226927, -113463, 26341, -3710, 350, -21, 1, 0, -5142061, 2571031, -603246, 87381, -8610, 602, -28, 1, 0, 134341711, -67170855, 15887845, -2346330, 240051, -17766
Offset: 0

Views

Author

Paul D. Hanna, Jan 10 2008

Keywords

Comments

A136590 is the triangle of trinomial logarithmic coefficients.
Column 1 is signed A048287, which is the number of semiorders on n labeled nodes whose incomparability graph is connected.
The Bell transform of (-1)^n*A048287(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, 7, -3, 1;
0, -61, 31, -6, 1;
0, 751, -375, 85, -10, 1;
0, -11821, 5911, -1350, 185, -15, 1;
0, 226927, -113463, 26341, -3710, 350, -21, 1;
0, -5142061, 2571031, -603246, 87381, -8610, 602, -28, 1;
0, 134341711, -67170855, 15887845, -2346330, 240051, -17766, 966, -36, 1; ...
		

Crossrefs

Cf. columns: A048287, A136596, A136597; A136590 (matrix inverse); A136588, A136589.

Programs

  • Maple
    # The function BellMatrix is defined in A264428.
    BellMatrix(n -> (-1)^n*A048287(n+1), 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[Sum[(-1)^(k+1) k! StirlingS2[#+1, k] CatalanNumber[k-1], {k, 1, #+1}]&, rows];
    Table[M[[n, k]], {n, 1, rows}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jun 24 2018, after Peter Luschny *)
  • PARI
    {T(n,k) = if(n
    				
  • PARI
    /* Define Stirling2: */
    {Stirling2(n,k) = n!*polcoeff(((exp(x+x*O(x^n))-1)^k)/k!,n)}
    /* Define Catalan(m,n) = [x^n] C(x)^m: */
    {CATALAN(m,n) = binomial(2*n+m,n) * m/(2*n+m)}
    /* Define this triangle: */
    {T(n,k) = if(n
    				
  • Sage
    # uses[bell_matrix from A264428]
    bell_matrix(lambda n: (-1)^n*A048287(n+1), 10) # Peter Luschny, Jan 18 2016

Formula

T(n,k) = Sum_{i=0..n-1} (-1)^i * (k+i)! * Stirling2(n,k+i) * Catalan(k,i)/k!, where Stirling2(n,k) = A008277(n,k); Catalan(k,i) = C(2i+k,i)*k/(2i+k) = coefficient of x^i in C(x)^k with C(x) = (1-sqrt(1-4x))/(2x).

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!.

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)))

A048287 Number of semiorders on n labeled nodes whose incomparability graph is connected.

Original entry on oeis.org

1, 1, 7, 61, 751, 11821, 226927, 5142061, 134341711, 3975839341, 131463171247, 4803293266861, 192178106208271, 8356430510670061, 392386967808249967, 19788154572706556461, 1066668756919315412431, 61204224384073232815981
Offset: 1

Views

Author

Keywords

Examples

			a(3)=7, the seven semiorders being three disjoint points and the disjoint union of a point and a two-element chain (with six labelings).
		

Crossrefs

Programs

  • Maple
    A048287 := n -> add((-1)^(n-k-1)*Stirling2(n,k+1)*(2*k)!/k!, k=0..n-1):
    seq(A048287(n), n=1..18); # Peter Luschny, Jan 27 2016
  • Mathematica
    Table[Sum[(-1)^(n - k) StirlingS2[n, k] k!*CatalanNumber[k - 1], {k, n}], {n, 20}] (* Michael De Vlieger, Jan 27 2016 *)
    Rest[Range[0, 18]! CoefficientList[Series[1 - 2 (1 - Exp[-x]) /(1 - Sqrt[4 Exp[-x] - 3]), {x, 0, 18}], x]] (* Vincenzo Librandi, Jan 28 2016 *)
  • PARI
    {a(n)=local(A136590=matrix(n+1,n+1,r,c,if(r>=c,(r-1)!/(c-1)!*polcoeff(log(1+x+x^2 +x*O(x^n))^(c-1),r-1))));(-1)^(n+1)*(A136590^-1)[n+1,2]} \\ Paul D. Hanna, Jan 10 2008
    
  • PARI
    {a(n) = if( n<0, 0, n! * polcoeff( (1 - sqrt(4*exp(-x + x*O(x^n)) - 3)) / 2, n))}; /* Michael Somos, Nov 26 2017 */
    
  • PARI
    {a(n) = if( n<1, 0, n! * polcoeff( serreverse( -log(1 - x + x^2 + x * O(x^n))), n))}; /* Michael Somos, Nov 26 2017 */

Formula

E.g.f.: 1-2*(1-exp(-x))/(1-sqrt(4*exp(-x)-3)).
E.g.f.: (1 - sqrt(4*exp(-x) - 3)) / 2. - Michael Somos, Nov 26 2017
a(n) = Sum_{k=1..n} (-1)^(n-k)*Stirling2(n, k)*k!*Catalan(k-1). - Vladeta Jovovic, Oct 18 2003
Equals column 1 (unsigned) of triangle A136595, which is the matrix inverse of the triangle A136590 of trinomial logarithmic coefficients. - Paul D. Hanna, Jan 10 2008
E.g.f A(x)=F(exp(x)-1), F(x)=x*A005043(x). - Vladimir Kruchinin, Sep 07 2010
a(n) = (-1)^(n-1) + Sum_{k=1..n-1} binomial(n,k)*a(k)*a(n-k). - Robert Israel, Mar 01 2016
Given e.g.f. =: A(x), then exp(-x) = A(x)^2 - A(x) + 1 = A'(x)*(1 - 2*A(x)). - Michael Somos, Nov 26 2017
a(n) ~ sqrt(3/8) * n^(n-1) / (log(4/3)^(n - 1/2) * exp(n)). - Vaclav Kotesovec, Dec 16 2020

Extensions

More terms from Vladeta Jovovic, Oct 18 2003
Showing 1-6 of 6 results.