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A204632 Least k such that n*k!! contains every digit at least once. 1
34, 30, 37, 28, 27, 28, 27, 39, 34, 34, 36, 36, 35, 27, 30, 34, 25, 34, 31, 30, 27, 29, 27, 30, 33, 35, 34, 44, 31, 37, 25, 32, 33, 28, 33, 36, 26, 30, 35, 28, 29, 32, 31, 30, 28, 27, 29, 38, 30, 27, 25, 35, 33, 29, 36, 33, 37, 32, 34, 28, 29, 33, 26, 22, 29 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A property of this sequence: the arithmetic mean s(x) = (1/x) *Sum_{k = 1..x} a(k) is very slowly decreasing when x increases. For example, s(100) = 30.89; s(1000) = 29.795 ; s(10000) = 28.1319 ; s(100000) = 26.53411. For almost all n, a(n) = 0 (see A204598).

LINKS

Table of n, a(n) for n=1..65.

EXAMPLE

a(2) = 30 because 2*30!! =  2* 42849873690624000 = 85699747381248000 contains every digit at least once.

MATHEMATICA

Table[k=1; While[!Length[Union[IntegerDigits[n*k!!]]]==10, k++]; k, {n, 1, 60}]

CROSSREFS

Cf. A006882, A204598.

Sequence in context: A214038 A070727 A298894 * A098023 A302209 A022990

Adjacent sequences:  A204629 A204630 A204631 * A204633 A204634 A204635

KEYWORD

nonn,base

AUTHOR

Michel Lagneau, Jan 17 2012

STATUS

approved

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Last modified October 14 11:55 EDT 2019. Contains 327999 sequences. (Running on oeis4.)