A154882 a(n) is the smallest number with at least as many divisors as a(n-1)^2.

2, 4, 12, 120, 7560, 8648640, 1927522396800, 4747472432036420486400, 128438082648984172330026178330296384000, 6184173455628205993842062057864303743050691444602955105860128640000

Offset: 1

Author

J. Lowell, Jan 16 2009

Keywords

• nonn

Examples

			4^2 = 16 has 5 divisors; the smallest number with at least 5 divisors is 12.
		

Formula

a(n) = A061799(A048691(a(n-1))). - R. J. Mathar, Jan 21 2009

Extensions

a(6)-a(10) from Donovan Johnson, May 09 2009