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Triangular array: T(n,1) = T(n,n) = n and T(n,k) = lcm(T(n-1,k-1), T(n-1,k)) for 1 < k < n.
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%I #11 Apr 25 2018 13:58:07

%S 1,2,2,3,2,3,4,6,6,4,5,12,6,12,5,6,60,12,12,60,6,7,60,60,12,60,60,7,8,

%T 420,60,60,60,60,420,8,9,840,420,60,60,60,420,840,9,10,2520,840,420,

%U 60,60,420,840,2520,10,11,2520,2520,840,420,60,420,840,2520,2520,11,12

%N Triangular array: T(n,1) = T(n,n) = n and T(n,k) = lcm(T(n-1,k-1), T(n-1,k)) for 1 < k < n.

%C T(2*n-1,n) = A058312(n-1) for n <= 13.

%e Triangle begins:

%e 1

%e 2 2

%e 3 2 3

%e 4 6 6 4

%e 5 12 6 12 5

%e 6 60 12 12 60 6

%e 7 60 60 12 60 60 7

%o (PARI) T(n,k) = if ((k==1) || (k==n), n, lcm(T(n-1,k-1), T(n-1,k)));

%o tabl(nn) = for (n=1, nn, for (k=1, n, print1(T(n,k), ", ")); print); \\ _Michel Marcus_, Apr 25 2018

%Y Cf. A080046.

%Y T(n, 2) = A003418(n-1) for n > 2.

%K nonn,tabl

%O 1,2

%A _Reinhard Zumkeller_, Jan 22 2003