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 A230709 #10 Dec 15 2018 11:49:31 %S A230709 0,2,3,4,5,6,8,9,10,12,14,15,16,17,18,20,22,23,24,26,27,28,29,30,32, %T A230709 33,34,36,38,39,40,42,43,44,45,46,48,50,51,52,53,54,56,57,58,60,62,63, %U A230709 64,65,66,68,70,71,72,74,75,76,77,78,80,82,83,84,85,86,88 %N A230709 Union of even odious (cf. A128309) and evil numbers (cf. A001969). %C A230709 Apart from initial zero: numbers m, such that when mergesorting lists of length m, the maximal number of comparisons is odd: A003071(a(n+1)) = A230721(n). %H A230709 Reinhard Zumkeller, <a href="/A230709/b230709.txt">Table of n, a(n) for n = 1..10000</a> %H A230709 <a href="/index/So#sorting">Index entries for sequences related to sorting</a> %F A230709 A010060(a(n)) * a(n) mod 2 = 0. %t A230709 Complement[Range[0, m = 88], Select[Range[1, m, 2], OddQ[ Total[ IntegerDigits[#, 2]]]&]] (* _Jean-François Alcover_, Dec 15 2018 *) %o A230709 (Haskell) %o A230709 a230709 n = a230709_list !! (n-1) %o A230709 a230709_list = filter (\x -> a010060 x * x `mod` 2 == 0) [0..] %o A230709 (PARI) is(n)=if(hammingweight(n)%2,n%2==0,1) \\ _Charles R Greathouse IV_, May 09 2016 %Y A230709 Cf. A092246 (complement). %K A230709 nonn,easy %O A230709 1,2 %A A230709 _Reinhard Zumkeller_, Oct 28 2013