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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.

A197419 Triangle with the numerator of the coefficient [x^k] of the second order Bernoulli polynomial B_n^(2)(x) in row n, column 0<=k<=n.

Original entry on oeis.org

1, -1, 1, 5, -2, 1, -1, 5, -3, 1, 1, -2, 5, -4, 1, 1, 1, -5, 25, -5, 1, -5, 1, 3, -10, 25, -6, 1, -1, -5, 7, 7, -35, 35, -7, 1, 7, -4, -10, 28, 7, -28, 70, -8, 1, 3, 21, -6, -10, 21, 63, -42, 30, -9, 1, -15, 3, 21, -20, -25, 42, 21, -60, 75, -10, 1, -5, -15, 33, 77, -55, -55, 77, 33, -165, 275, -11, 1, 7601, -10, -45, 66, 231, -132, -110, 132, 99, -110, 55, -12, 1
Offset: 0

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Author

R. J. Mathar, Oct 14 2011

Keywords

Comments

The a-th order Bernoulli polynomials are defined via the exponential generating function (t/(exp t -1))^a*exp(x*t) = sum_{n>=0} B_n^(a)(x) * t^n/n!. The current triangular array shows the coefficient [x^k] of B_n^(2)(x), i.e. the expansion coefficients in rising powers of the polynomial of x with a=2.
P(n,x) = x^n + 2*Sum_{m=0..n-1} binomial(n,m)*x^m*Sum_{k=1..n-m} stirling2(n-m,k)*stirling1(2+k,2)/((k+1)*(k+2)). - Vladimir Kruchinin, Oct 23 2011

Examples

			The table of the coefficients is
  1;
  -1,1;
  5/6,-2,1;     5/6-2x+x^2
  -1/2,5/2,-3,1;   -1/2+5x/2-3x^2+x^3
  1/10,-2,5,-4,1;
  1/6,1/2,-5,25/3,-5,1;
  -5/42,1,3/2,-10,25/2,-6,1;
  -1/6,-5/6,7/2,7/2,-35/2,35/2,-7,1;
  7/30,-4/3,-10/3,28/3,7,-28,70/3,-8,1;
  3/10,21/10,-6,-10,21,63/5,-42,30,-9,1;
  -15/22,3,21/2,-20,-25,42,21,-60,75/2,-10,1;
  -5/6,-15/2,33/2,77/2,-55,-55,77,33,-165/2,275/6,-11,1;
  7601/2730,-10,-45,66,231/2,-132,-110,132,99/2,-110,55,-12,1;
		

Crossrefs

Cf. A197420 (denominator), A100616, A100615 (column k=0).

Programs

  • Maple
    A197419 := proc(n,k)
            local a,Bt,Bnx,o ,t,x;
            a := 2 ;
            Bt := (t/(exp(t)-1))^a*exp(x*t) ;
            Bnx := n!*coeftayl(Bt,t=0,n) ;
            coeftayl(Bnx,x=0,k) ;
            numer(%) ;
    end proc:
    seq(seq(A197419(n,k),k=0..n),n=0..4) ; # print row by row
  • Mathematica
    t[n_, m_] := If [n == m, 1, 2*Binomial[n, m]*Sum[StirlingS2[n-m, k]*StirlingS1[2+k, 2]/((k+1)*(2+k)), {k, 1, n-m}]]; Table[t[n, m] // Numerator, {n, 0, 12}, {m, 0, n}] // Flatten (* Jean-François Alcover, Dec 12 2013, after Vladimir Kruchinin *)
  • Maxima
    T(n,m):=num(if n=m then 1 else 2*binomial(n,m)* sum(stirling2(n-m,k) *stirling1(2+k,2)/ ((k+1)*(2+k)),k,1,n-m)); /* Vladimir Kruchinin, Oct 23 2011 */

Formula

T(n,m) = 2*binomial(n,m)*Sum_{k=1..n-m} Stirling2(n-m,k)*Stirling1(2+k,2)/((k+1)*(k+2)), mVladimir Kruchinin, Oct 23 2011