A242211 a(1) = 4, a(n) = A222208(a(n-1)).

4, 6, 12, 36, 144, 1296, 20736, 1679616, 429981696

Offset: 1

Author

J. Lowell, May 07 2014

Keywords

• nonn
• more

Comments

The definition "a(1) = 2, a(n) = A222208(a(n-1))" produces the periodic sequence 2, 3, 2, 3, 2, 3, 2, ... .

From Lechoslaw Ratajczak, May 23 2022: (Start)

It appears that a(n) = 2^(2^floor((n-1)/2))*3^(2^floor((n-2)/2)) (for n > 1). If it is true, a(10) = 2821109907456.

The definition "b(1) = 8, b(k) = A222208(b(k-1))" produces the sequence: 8, 18, 48, 324, 2304, 104976, ... . It appears that b(k) = 2^A135530(k-1)*3^A135530(k-2) (for k > 1). (End)

Examples

			a(3) = 12 because a(2) = 6 and A222208(6) = 12.
		

Crossrefs

Cf. A222208, A222209.

Extensions

a(8) from Alois P. Heinz, May 07 2014

a(9) from Sean A. Irvine, Jul 18 2022