This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A249686 #19 Nov 12 2014 23:19:05 %S A249686 0,0,0,1,0,1,2,1,2,3,2,5,6,5,6,7,6,5,10,9,8,7,6,7,10,9,10,13,12,13,16, %T A249686 15,14,15,14,13,16,15,14,15,14,13,16,15,16,17,16,17,16,15,16,17,16,17, %U A249686 18,17,20,21,20,23,28,27,26,27,26,25,30,29,28,27,26,25,28 %N A249686 After A084937(n) has been computed, let m = largest term so far in A084937. Then a(n) = number of positive integers < m that are missing from A084937 at this point. %C A249686 Running count of missing numbers in A084937. %C A249686 It appears that at any point, the number of missing even numbers from A084937 is always much larger than the number of missing odd numbers. It would be nice to have a more precise statement of this property. %C A249686 In this regard, it would be helpful to have two further sequences, one giving the number of even missing numbers at each point, the other giving the number of odd missing numbers. These are now A250099, A250100. See also A249777, A249856, A249867. %H A249686 N. J. A. Sloane, <a href="/A249686/b249686.txt">Table of n, a(n) for n = 1..100000</a> %e A249686 After step 7 of A084937, here is what we have: %e A249686 1 2 3 4 5 6 7 ... n %e A249686 1 2 3 5 4 7 9 ... A084937(n) %e A249686 so m = 9, and the missing numbers < 9 are 6 and 8, so a(7) = 2. %Y A249686 Cf. A084937, A250099, A250100. See A249777, A249856, A249857, A249858 for another way of looking at this question. %K A249686 nonn %O A249686 1,7 %A A249686 _N. J. A. Sloane_, Nov 05 2014