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 A109878 Triangle read by rows: see below. 0

%I

%S 1,1,1,1,2,3,2,6,12,4,6,24,60,20,10,24,120,360,120,60,36,120,720,2520,

%T 840,420,252,168,720,5040,20160,6720,3360,2016,1344,960,5040,40320,

%U 181440,60480,30240,18144,12096,8640,6480,40320,362880,1814400,604800

%N Triangle read by rows: see below.

%e Consider the formula n! = 1*2*3...*(n-2) + 2*3*4...*(n-1)+ ...+ (n-1)*n*1*2...(n-4) + n*1*2*3*...*(n-3). E.g., 5! = 1*2*3 +2*3*4 +3*4*5 + 4*5*1 + 5*1*2.

%e Consider the following triangle of partition of n! based on above formula.

%e 1

%e 1 1

%e 1 2 3

%e 2 6 12 4

%e 6 24 60 20 10

%e 24 120 360 120 60 36

%e ...

%e Sequence contains the triangle by rows.

%t f[n_] := Times @@@ Sort[Partition[Range[n], n - 2, 1, {-1, -1}]]; Flatten[ Table[ f[n], {n, 2, 10}]] (* _Robert G. Wilson v_, Jul 13 2005 *)

%K nonn,tabl

%O 1,5

%A _Amarnath Murthy_, Jul 10 2005

%E More terms from _Robert G. Wilson v_, Jul 18 2005

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Last modified January 23 07:25 EST 2022. Contains 350509 sequences. (Running on oeis4.)