A108862 Numbers k that divide the sum of the digits of (k!)^2.

1, 2, 3, 6, 9, 18, 34, 36, 54, 99, 111, 261, 648, 1161, 1296, 2763, 4735, 4784, 4911, 6327, 7929, 10599, 17352, 17541, 48372, 223956, 226185, 290502, 375480, 481207, 481620, 482567, 482801, 484412

Offset

1,2

Links

Table of n, a(n) for n=1..34.

Example

648 is a term because the sum of the digits in (648!)^2, 12312, is divisible by 648.

Mathematica

Do[If[Mod[Plus @@ IntegerDigits[(n!)^2], n] == 0, Print[n]], {n, 1, 10000}]

Crossrefs

Cf. A001044

Sequence in context: A091326 A113863 A085431 * A298413 A268610 A018582

Adjacent sequences: A108859 A108860 A108861 * A108863 A108864 A108865

Keyword

nonn,base,hard,more

Author

Ryan Propper, Jul 11 2005

Extensions

a(22)-a(25) from Robert Gerbicz, Aug 24 2006

a(26)-a(34) from Donovan Johnson, Dec 13 2010

Status

approved