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 A108858 Numbers k that divide the sum of the digits of k!!, the double factorial of k. 0

%I

%S 1,2,3,4,6,9,51,57,252,585,1131,2106,2172,2250,2292,26159,26769,27253,

%T 28071,46802,47148,48018

%N Numbers k that divide the sum of the digits of k!!, the double factorial of k.

%C Next term after 48018, if it exists, is greater than 100000.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/DoubleFactorial.html">Double Factorial</a>.

%e 585 is a term because the sum of the digits of 585!! = 2925 is divisible by 585.

%t Do[If[Mod[Plus @@ IntegerDigits[n!! ], n] == 0, Print[n]], {n, 1, 100000}]

%Y Cf. A006882.

%K nonn,base,hard,more

%O 1,2

%A _Ryan Propper_, Jul 11 2005

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Last modified February 2 05:15 EST 2023. Contains 359997 sequences. (Running on oeis4.)