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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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

LINKS

Table of n, a(n) for n=1..22.

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

Adjacent sequences: A108855 A108856 A108857 * A108859 A108860 A108861

KEYWORD

nonn,base,hard,more

AUTHOR

Ryan Propper, Jul 11 2005

STATUS

approved

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Last modified December 5 02:30 EST 2022. Contains 358572 sequences. (Running on oeis4.)