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A320824
T(n, k) = (m*n)!/(k!*(n-k)!)^m with m = 3; triangle read by rows, 0 <= k <= n.
2
1, 6, 6, 90, 720, 90, 1680, 45360, 45360, 1680, 34650, 2217600, 7484400, 2217600, 34650, 756756, 94594500, 756756000, 756756000, 94594500, 756756, 17153136, 3705077376, 57891834000, 137225088000, 57891834000, 3705077376, 17153136
OFFSET
0,2
FORMULA
T(n, k) = ((3*n)!/(n!)^3) * binomial(n, k)^3 = A006480(n)*A181543(n, k).
EXAMPLE
Triangle starts:
[0] 1;
[1] 6, 6;
[2] 90, 720, 90;
[3] 1680, 45360, 45360, 1680;
[4] 34650, 2217600, 7484400, 2217600, 34650;
[5] 756756, 94594500, 756756000, 756756000, 94594500, 756756;
MAPLE
T := (n, k, m) -> (m*n)!/(k!*(n-k)!)^m:
seq(seq(T(n, k, 3), k=0..n), n=0..7);
MATHEMATICA
Table[((3*n)!/(n!)^3)*Binomial[n, k]^3, {n, 0, 15}, {k, 0, n}]//Flatten (* G. C. Greubel, Oct 27 2018 *)
PROG
(PARI) t(n, k) = (3*n)!/(k!*(n-k)!)^3
trianglerows(n) = for(x=0, n-1, for(y=0, x, print1(t(x, y), ", ")); print(""))
/* Print initial 6 rows of triangle as follows: */
trianglerows(6) \\ Felix Fröhlich, Oct 21 2018
(Magma) [[(Factorial(3*n)/(Factorial(n))^3)*Binomial(n, k)^3: k in [0..n]]: n in [0..15]]; // G. C. Greubel, Oct 27 2018
(GAP) Flat(List([0..6], n->List([0..n], k->Factorial(3*n)/(Factorial(k)*Factorial(n-k))^3))); # Muniru A Asiru, Oct 27 2018
CROSSREFS
Cf. A007318 (Pascal, m=1), A069466 (m=2), this sequence (m=3).
Sequence in context: A146892 A347916 A361738 * A085804 A012125 A267139
KEYWORD
nonn,tabl
AUTHOR
Peter Luschny, Oct 21 2018
STATUS
approved