A079542 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.

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, 420, 60, 60, 60, 60, 420, 8, 9, 840, 420, 60, 60, 60, 420, 840, 9, 10, 2520, 840, 420, 60, 60, 420, 840, 2520, 10, 11, 2520, 2520, 840, 420, 60, 420, 840, 2520, 2520, 11, 12

Offset: 1

Author

Reinhard Zumkeller, Jan 22 2003

Keywords

• nonn
• tabl

Comments

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

Examples

			Triangle begins:
  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
		

Crossrefs

Cf. A080046.

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

Programs

PARI

T(n,k) = if ((k==1) || (k==n), n, lcm(T(n-1,k-1), T(n-1,k)));
tabl(nn) = for (n=1, nn, for (k=1, n, print1(T(n,k), ", ")); print); \\ Michel Marcus, Apr 25 2018