cp's OEIS Frontend

A099249 Number of numbers not greater than n such that length in binary representation and number of ones are coprime.

%I A099249 #25 Jul 27 2025 10:33:54
%S A099249 1,2,2,3,4,5,5,6,6,6,7,7,8,9,9,10,11,12,13,14,15,16,17,18,19,20,21,22,
%T A099249 23,24,24,25,25,25,25,25,25,25,25,25,25,25,25,25,25,25,26,26,26,26,26,
%U A099249 26,26,26,27,27,27,27,28,28,29,30,30,31,32,33,34,35,36,37,38,39,40,41
%N A099249 Number of numbers not greater than n such that length in binary representation and number of ones are coprime.
%C A099249 Number of numbers m <= n such that A099244(m) = 1.
%H A099249 Reinhard Zumkeller, <a href="/A099249/b099249.txt">Table of n, a(n) for n = 1..10000</a>
%H A099249 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>.
%F A099249 a(n) = Sum_{k=1..n} A063524(A099244(k)). - _Reinhard Zumkeller_, Oct 10 2013
%t A099249 Accumulate[Table[Boole[CoprimeQ[BitLength[n], DigitCount[n, 2, 1]]], {n, 1, 100}]] (* _Amiram Eldar_, Jul 16 2023 *)
%o A099249 (Haskell)
%o A099249 a099249 n = a099249_list !! (n-1)
%o A099249 a099249_list = scanl1 (+) $ map ((0 ^) . (subtract 1)) a099244_list
%o A099249 -- _Reinhard Zumkeller_, Oct 10 2013
%o A099249 (PARI) isA099247(k) = {my(b = binary(k)); gcd(#b, vecsum(b)) == 1;}
%o A099249 list(nmax) = {my(c = 0); for(n = 1, nmax, if(isA099247(n), c++); print1(c, ", "));} \\ _Amiram Eldar_, Jul 26 2025
%Y A099249 Cf. A000120, A007088, A063524, A070939, A099244, A099247.
%K A099249 nonn,base
%O A099249 1,2
%A A099249 _Reinhard Zumkeller_, Oct 08 2004