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A108858
Numbers k that divide the sum of the digits of k!!, the double factorial of k.
0
1, 2, 3, 4, 6, 9, 51, 57, 252, 585, 1131, 2106, 2172, 2250, 2292, 26159, 26769, 27253, 28071, 46802, 47148, 48018
OFFSET
1,2
COMMENTS
Next term after 48018, if it exists, is greater than 100000.
LINKS
Eric Weisstein's World of Mathematics, Double Factorial.
EXAMPLE
585 is a term because the sum of the digits of 585!! = 2925 is divisible by 585.
MATHEMATICA
Do[If[Mod[Plus @@ IntegerDigits[n!! ], n] == 0, Print[n]], {n, 1, 100000}]
CROSSREFS
Cf. A006882.
Sequence in context: A275173 A295394 A081419 * A294688 A094859 A267102
KEYWORD
nonn,base,hard,more
AUTHOR
Ryan Propper, Jul 11 2005
STATUS
approved