A054651
Triangle T(n,k) read by rows giving coefficients in expansion of n! * Sum_{i=0..n} C(x,i) in descending powers of x.
Original entry on oeis.org
1, 1, 1, 1, 1, 2, 1, 0, 5, 6, 1, -2, 11, 14, 24, 1, -5, 25, 5, 94, 120, 1, -9, 55, -75, 304, 444, 720, 1, -14, 112, -350, 1099, 364, 3828, 5040, 1, -20, 210, -1064, 3969, -4340, 15980, 25584, 40320, 1, -27, 366, -2646, 12873, -31563, 79064, 34236, 270576, 362880
Offset: 0
The first few polynomials are:
1, 1+x, 2+x+x^2, 6+5*x+x^3, 24+14*x+11*x^2-2*x^3+x^4, ...
So the triangle begins:
1;
1, 1;
1, 1, 2;
1, 0, 5, 6;
1, -2, 11, 14, 24;
1, -5, 25, 5, 94, 120;
1, -9, 55, -75, 304, 444, 720;
1, -14, 112, -350, 1099, 364, 3828, 5040;
1, -20, 210, -1064, 3969, -4340, 15980, 25584, 40320;
...
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c[n_, k_] := Product[n-i, {i, 0, k-1}]/k!; row[n_] := CoefficientList[ n!*Sum[c[x, k], {k, 0, n}], x] // Reverse; Table[ row[n], {n, 0, 9}] // Flatten (* Jean-François Alcover, Oct 04 2012 *)
A054655
Triangle T(n,k) giving coefficients in expansion of n!*binomial(x-n,n) in powers of x.
Original entry on oeis.org
1, 1, -1, 1, -5, 6, 1, -12, 47, -60, 1, -22, 179, -638, 840, 1, -35, 485, -3325, 11274, -15120, 1, -51, 1075, -11985, 74524, -245004, 332640, 1, -70, 2086, -34300, 336049, -1961470, 6314664, -8648640, 1, -92, 3682, -83720, 1182769
Offset: 0
Triangle begins:
1;
1, -1;
1, -5, 6;
1, -12, 47, -60;
1, -22, 179, -638, 840;
1, -35, 485, -3325, 11274, -15120;
1, -51, 1075, -11985, 74524, -245004, 332640;
1, -70, 2086, -34300, 336049, -1961470, 6314664, -8648640;
...
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a054655_row := proc(n) local k; seq(coeff(expand((-1)^n*pochhammer (n-x,n)),x,n-k),k=0..n) end: # Peter Luschny, Nov 28 2010
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row[n_] := Table[ Coefficient[(-1)^n*Pochhammer[n - x, n], x, n - k], {k, 0, n}]; A054655 = Flatten[ Table[ row[n], {n, 0, 8}]] (* Jean-François Alcover, Apr 06 2012, after Maple *)
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T(n,k)=polcoef(n!*binomial(x-n,n), n-k);
A257635
Triangle with n-th row polynomial equal to Product_{k = 1..n} (x + n + k).
Original entry on oeis.org
1, 2, 1, 12, 7, 1, 120, 74, 15, 1, 1680, 1066, 251, 26, 1, 30240, 19524, 5000, 635, 40, 1, 665280, 434568, 117454, 16815, 1345, 57, 1, 17297280, 11393808, 3197348, 495544, 45815, 2527, 77, 1, 518918400, 343976400, 99236556, 16275700, 1659889, 107800, 4354, 100, 1
Offset: 0
Triangle begins:
[0] 1;
[1] 2, 1;
[2] 12, 7, 1;
[3] 120, 74, 15, 1;
[4] 1680, 1066, 251, 26, 1;
[5] 30240, 19524, 5000, 635, 40, 1;
[6] 665280, 434568, 117454, 16815, 1345, 57, 1;
...
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seq(seq(coeff(product(n + x + k, k = 1 .. n), x, i), i = 0..n), n = 0..8);
# Alternative:
p := n -> n!*hypergeom([-n, -x + n], [-n], 1):
seq(seq((-1)^k*coeff(simplify(p(n)), x, k), k=0..n), n=0..6); # Peter Luschny, Nov 27 2021
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p[n_, x_] := FunctionExpand[Gamma[2*n + x + 1] / Gamma[n + x + 1]];
Table[CoefficientList[p[n, x], x], {n,0,8}] // Flatten (* Peter Luschny, Mar 21 2022 *)
A347985
a(n) = [x^n] (2*n)! * Sum_{k=0..2*n} binomial(x-2*n,k).
Original entry on oeis.org
1, -3, 131, -8955, 893249, -117408375, 19180128407, -3747886705563, 852713408774513, -221431482383149467, 64629367172619230475, -20945446993569455512155, 7463226827397324296491489, -2899926767958744905966692575
Offset: 0
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a(n) = (2*n)!*polcoef(sum(k=n, 2*n, binomial(x-2*n, k)), n);
Showing 1-4 of 4 results.
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