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A101821 Triangle read by rows: T(n,h) = number of functions f:{1,2,...,n}->{1,2,...,n-2} such that |Image(f)|=h, h=1,2,...,n-2; n=3,4,.... 4

%I #4 Mar 30 2012 18:57:06

%S 2,3,42,4,180,600,5,620,5400,7800,6,1890,36120,126000,100800,7,5534,

%T 202860,1428840,2646000,1340640,8,14280,1016400,13053600,46710720,

%U 53343360,18627840,9,36792,4702320,103133520,642978000,1380576960

%N Triangle read by rows: T(n,h) = number of functions f:{1,2,...,n}->{1,2,...,n-2} such that |Image(f)|=h, h=1,2,...,n-2; n=3,4,....

%F T(n, h) = C(n-2, h)*U(n, h), where U(n, h) is the array in A019538.

%e First rows:

%e 2

%e 3 42

%e 4 180 600

%e 5 620 5400 7800

%Y Cf. A019538, A101817, A101819.

%K nonn,tabl

%O 0,1

%A _Clark Kimberling_, Dec 17 2004

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Last modified August 14 03:23 EDT 2024. Contains 375146 sequences. (Running on oeis4.)