A046792 - OEIS

%I #10 Mar 08 2020 00:21:04

%S 1,1,1,1,6,1,1,60,60,1,1,840,10080,840,1,1,15120,3326400,3326400,

%T 15120,1,1,332640,1816214400,36324288000,1816214400,332640,1,1,

%U 8648640,1482030950400,844757641728000,844757641728000,1482030950400,8648640,1

%N Triangle of numbers where k-th row contains (ij)!/(i!j!) with i+j = k+1, 1 <= i <= k.

%H Andrew Howroyd, <a href="/A046792/b046792.txt">Table of n, a(n) for n = 1..210</a>

%F T(n,k) = (k*(n+1-k))!/(k!*(n+1-k)!). - _Andrew Howroyd_, Mar 07 2020

%e Triangle begins

%e   1;

%e   1,  1;

%e   1,  6,  1;

%e   1, 60, 60,  1;

%e   ...

%o (PARI) T(n,k)={(k*(n+1-k))!/(k!*(n+1-k)!)} \\ _Andrew Howroyd_, Mar 07 2020

%K nonn,tabl,easy

%O 1,5

%A _N. J. A. Sloane_

%E More terms from _James A. Sellers_