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 A127254 #12 Aug 06 2023 03:05:07 %S A127254 1,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,1,1,1,1,0,1, %T A127254 1,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1,1,1, %U A127254 1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,1 %N A127254 (0,1) sequence whose zero positions are indexed by twice the odious numbers given by A091855. %C A127254 0's appear at positions indexed by 2*A091855(n). %H A127254 Antti Karttunen, <a href="/A127254/b127254.txt">Table of n, a(n) for n = 0..65537</a> %H A127254 <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>. %t A127254 a[n_] := If[EvenQ[n] && EvenQ[IntegerExponent[n/2, 2]] && OddQ[DigitCount[n/2, 2, 1]], 0, 1]; Array[a, 100, 0] (* _Amiram Eldar_, Aug 06 2023 *) %o A127254 (PARI) A127254(n) = if(n%2,1,!(hammingweight(n)%2 && !(valuation(n/2, 2)%2))); \\ After PARI-code in A091855. - _Antti Karttunen_, Nov 02 2018 %Y A127254 Row sums of A127253. %Y A127254 Cf. A000069, A091855. %K A127254 nonn,base %O A127254 0,1 %A A127254 _Paul Barry_, Jan 10 2007 %E A127254 More terms from _Antti Karttunen_, Nov 02 2018