A179214 Product of squarefree numbers between n and 2*n (inclusive).

2, 6, 90, 210, 2100, 4620, 140140, 300300, 5105100, 96996900, 4481256780, 9369900540, 243617414040, 18739801080, 1164544781400, 2406725881560, 2700346439110320, 5559536786403600, 7816708721683461600

Offset: 1

Author

Reinhard Zumkeller, Jul 05 2010

Keywords

• nonn

Comments

A073838(n) <= a(n) <= A126804(n);

a(n) = A179215(2*n)/A179215(n-1).

Examples

			a(10) = 10*11*13*14*15*17*19 = 96996900;
a(11) = 11*13*14*15*17*19*21*22 = 4481256780;
a(12) = 13*14*15*17*19*21*22*23 = 9369900540.
		

Crossrefs

Cf. A179211, A179213, A005117.

Formula

a(n) = PROD(k^A008966(k): n <= k <= 2*n).

Extensions

Example corrected by Reinhard Zumkeller, Jul 19 2010