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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.

A247497 Triangle read by rows, T(n,k) (n>=0, 0<=k<=n) coefficients of the partial fraction decomposition of rational functions generating the columns of A247495 (the Motzkin polynomials evaluated at nonnegative integers).

Original entry on oeis.org

1, 1, 1, 2, 3, 2, 4, 10, 12, 6, 9, 33, 62, 60, 24, 21, 111, 300, 450, 360, 120, 51, 378, 1412, 3000, 3720, 2520, 720, 127, 1303, 6552, 18816, 32760, 34440, 20160, 5040, 323, 4539, 30186, 113820, 264264, 388080, 352800, 181440, 40320
Offset: 0

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Author

Peter Luschny, Dec 13 2014

Keywords

Examples

			Triangle starts:
[  1],
[  1,    1],
[  2,    3,    2],
[  4,   10,   12,     6],
[  9,   33,   62,    60,    24],
[ 21,  111,  300,   450,   360,   120],
[ 51,  378, 1412,  3000,  3720,  2520,   720],
[127, 1303, 6552, 18816, 32760, 34440, 20160, 5040].
.
[n=3] -> [4,10,12,6] -> 4/(x-1)+10/(x-1)^2+12/(x-1)^3+6/(x-1)^4 = 2*x*(-x+2*x^2+2)/(x-1)^4; generating function of A247495[n,3] = 0,4,14, 36,...
[n=4] -> [9,33,62,60,24] -> -9/(x-1)-33/(x-1)^2-62/(x-1)^3-60/(x-1)^4-24/(x-1)^5 = -(2-x-3*x^3+17*x^2+9*x^4)/(x-1)^5; generating function of A247495[n,4] = 2,9,42,137,...
		

Crossrefs

Programs

  • Maple
    A247497_row := proc(n) local A, M, p;
    A := (n,k) -> `if`(type(n-k, odd),0,n!/(k!*((n-k)/2)!^2*((n-k)/2+1))):
    M := (k,x) -> add(A(k,j)*x^j,j=0..k): # Motzkin polynomial
    p := expand(sum(x^k*M(n,k),k=0..infinity));
    [seq((-1)^(n+1)*coeff(convert(p,parfrac),(x-1)^(-j)),j=1..n+1)] end:
    seq(print(A247497_row(n)),n=0..7);

Formula

Let M_{n}(x) = sum_{k=0..n} A097610(n,k)*x^k denote the Motzkin polynomials. The T(n,k) are implicitly defined by:
sum_{k=0..n} (-1)^(n+1)*T(n,k)/(x-1)^(k+1) = sum_{k>=0} x^k*M_n(k).
T(n, 0) = A001006(n) (Motzkin numbers).
T(n, n) = A000142(n) = n!.
T(n, 1) = A058987(n+1) for n>=1.
T(n,n-1)= A001710(n+1) for n>=1.