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A281072 Smallest number k > 0 such that b - r is even or r = 0 for all b = 1..n, r == k mod b.

%I A281072 #12 Jan 19 2017 23:49:06
%S A281072 1,2,4,4,6,6,10,10,10,10,36,36,66,66,196,196,196,196,568,568,568,568,
%T A281072 1008,1008,1288,1288,1288,1288,8398,8398,8730,8730,50688,50688,124738,
%U A281072 124738,124738,124738,155296,155296,155296,155296,155296,155296,155296,155296,1784476,1784476
%N A281072 Smallest number k > 0 such that b - r is even or r = 0 for all b = 1..n, r == k mod b.
%C A281072 a(n) is the smallest number for which A281071(a(n)) is greater than or equal to n.
%H A281072 Martin Janecke, <a href="/A281072/b281072.txt">Table of n, a(n) for n = 1..88</a>
%e A281072 a(3) = 4 because
%e A281072   1 mod 2 = 1 where r > 0 and 2 - 1 is odd;
%e A281072   2 mod 3 = 2 where r > 0 and 3 - 2 is odd;
%e A281072   3 mod 2 = 1 where r > 0 and 2 - 1 is odd;
%e A281072   4 mod 1 = 0 where r = 0,
%e A281072   4 mod 2 = 0 where r = 0,
%e A281072   4 mod 3 = 1 where 3 - 1 is even.
%Y A281072 Cf. A281071.
%K A281072 nonn,easy
%O A281072 1,2
%A A281072 _Martin Janecke_, Jan 14 2017