A121826 a(n) = Product_{k=1..n} D(k), where D() are the doublets, A020338.

11, 242, 7986, 351384, 19326120, 1275523920, 98215341840, 8642950081920, 855652058110080, 864208578691180800, 960135730925901868800, 1163684505882193064985600, 1527917756223319494326092800, 2160475707299773764977095219200, 3273120696559157253940299257088000

Offset: 1

Author

Jason Earls, Aug 27 2006

Keywords

• easy
• base
• nonn

Comments

a(n) is divisible by n! because D(k) is divisible by k. - Michel Marcus, Jan 07 2021

Examples

			a(4)=351384 because 11*22*33*44 = 351384.
		

Crossrefs

Cf. A000142, A020338.

Programs

PARI

D(n) = eval(Str(n, n)); \\ A020338
a(n) = prod(k=1, n, D(k)); \\ Michel Marcus, Jan 07 2021