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 A099247 #20 Jul 27 2025 10:33:51
%S A099247 1,2,4,5,6,8,11,13,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,32,
%T A099247 47,55,59,61,62,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,
%U A099247 82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103
%N A099247 Numbers such that, in binary representation, the length and the number of ones are coprime.
%H A099247 Reinhard Zumkeller, <a href="/A099247/b099247.txt">Table of n, a(n) for n = 1..10000</a>
%H A099247 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>.
%F A099247 A099244(a(n)) = 1.
%t A099247 Select[Range[150],CoprimeQ[IntegerLength[#,2],DigitCount[#,2,1]]&] (* _Harvey P. Dale_, Sep 22 2012 *)
%o A099247 (Haskell)
%o A099247 a099247 n = a099247_list !! (n-1)
%o A099247 a099247_list = filter ((== 1) . a099244) [1..]
%o A099247 -- _Reinhard Zumkeller_, Oct 10 2013
%o A099247 (PARI) isok(k) = {my(b = binary(k)); gcd(#b, vecsum(b)) == 1;} \\ _Amiram Eldar_, Jul 26 2025
%Y A099247 Complement of A099248.
%Y A099247 Cf. A070939, A000120, A007088, A099244, A099249.
%K A099247 nonn,base
%O A099247 1,2
%A A099247 _Reinhard Zumkeller_, Oct 08 2004
%E A099247 Definition clarified by _Harvey P. Dale_, Sep 22 2012