|
%I #6 Mar 30 2012 18:36:00
%S 34,30,37,28,27,28,27,39,34,34,36,36,35,27,30,34,25,34,31,30,27,29,27,
%T 30,33,35,34,44,31,37,25,32,33,28,33,36,26,30,35,28,29,32,31,30,28,27,
%U 29,38,30,27,25,35,33,29,36,33,37,32,34,28,29,33,26,22,29
%N Least k such that n*k!! contains every digit at least once.
%C 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).
%e a(2) = 30 because 2*30!! = 2* 42849873690624000 = 85699747381248000 contains every digit at least once.
%t Table[k=1;While[!Length[Union[IntegerDigits[n*k!!]]]==10,k++];k,{n,1,60}]
%Y Cf. A006882, A204598.
%K nonn,base
%O 1,1
%A _Michel Lagneau_, Jan 17 2012
|
