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

1,1

Comments

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

Links

Table of n, a(n) for n=1..15.

Example

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

Prog

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

Crossrefs

Cf. A000142, A020338.

Sequence in context: A267642 A267665 A196258 * A041223 A041220 A347483

Adjacent sequences: A121823 A121824 A121825 * A121827 A121828 A121829

Keyword

easy,base,nonn

Author

Jason Earls, Aug 27 2006

Status

approved