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.

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A156654 Triangle T(n, k) = coefficients of p(x,n), where p(x,n) = ((1-x)^(2*n+1)/x^n) * Sum_{j >= n} ( (2*j+1)^n * binomial(j, n) * x^j ), read by rows.

Original entry on oeis.org

1, 3, 1, 25, 22, 1, 343, 515, 101, 1, 6561, 14156, 5766, 396, 1, 161051, 456197, 299342, 49642, 1447, 1, 4826809, 16985858, 15796159, 4592764, 371239, 5090, 1, 170859375, 719818759, 878976219, 383355555, 58474285, 2550165, 17481, 1, 6975757441, 34264190872, 52246537948, 31191262504, 7488334150, 660394024, 16574428, 59032, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 12 2009

Keywords

Examples

			Triangle begins as:
          1;
          3,         1;
         25,        22,         1;
        343,       515,       101,         1;
       6561,     14156,      5766,       396,        1;
     161051,    456197,    299342,     49642,     1447,       1;
    4826809,  16985858,  15796159,   4592764,   371239,    5090,     1;
  170859375, 719818759, 878976219, 383355555, 58474285, 2550165, 17481, 1;
		

Crossrefs

Programs

  • Magma
    m:= 40; R:=PowerSeriesRing(Rationals(), m);
    T:= func< n | Coefficients(R!( ((1-x)^(2*n+1)/x^n)*(&+[ (2*j+1)^n*Binomial(j, n)*x^j: j in [n..m]] ) )) >;
    [T(n): n in [0..12]]; // G. C. Greubel, Apr 02 2021
    
  • Mathematica
    p[x_, n_]:= ((1-x)^(2*n+1)/x^n)*Sum[(2*j+1)^n*Binomial[j, n]*x^j, {j,n,2*n}];
    Table[CoefficientList[Series[p[x,n], {x,0,n}], x], {n,0,12}]//Flatten (* modified by G. C. Greubel, Apr 02 2021 *)
  • Sage
    def p(n, x): return ((1-x)^(2*n+1)/x^n)*sum( (2*j+1)^n*binomial(j, n)*x^j for j in (n..2*n) )
    flatten([[( p(n, x) ).series(x, n+1).list()[k] for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Apr 02 2021

Formula

Define p(x,n) = ((1-x)^(2*n+1)/x^n) * Sum_{j >= n} ( (2*j+1)^n * binomial(j, n) * x^j ) then the triangle is defined by T(n, k) = coefficients of p(x,n) for row n and column k.
Sum_{k=0..n} T(n,k) = 2^(n-1) * n! * Catalan(n-1) = A144828(n) = A052714(n+1). - G. C. Greubel, Apr 02 2021

Extensions

Edited by G. C. Greubel, Apr 02 2021
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