The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A093696 Numbers n such that all divisors of n have an odd number of 1's in their binary expansions. 6
 1, 2, 4, 7, 8, 11, 13, 14, 16, 19, 22, 26, 28, 31, 32, 37, 38, 41, 44, 47, 49, 52, 56, 59, 61, 62, 64, 67, 73, 74, 76, 79, 82, 88, 91, 94, 97, 98, 103, 104, 107, 109, 112, 118, 121, 122, 124, 127, 128, 131, 133, 134, 137, 143, 146, 148, 151, 152, 157, 158, 164, 167, 173 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Subsequence of A000069. - Michel Marcus, Feb 09 2014 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 EXAMPLE 14 is in the sequence because its divisors are [1, 2, 7, 14] and in binary: 1, 10, 111 and 1110, all have an odd number of 1's. MAPLE isA001969 := proc(n)     if wt(n) mod 2 = 0 then         true;     else         false;     end if; end proc: isA093696 := proc(n)     for d in numtheory[divisors](n) do         if isA001969(d) then             return false;         end if;     end do;     true; end proc: for n from 1 to 200 do     if isA093696(n) then         printf("%d, ", n);     end if; end do: # R. J. Mathar, Feb 13 2014 MATHEMATICA odiousQ[n_] := OddQ @ DigitCount[n, 2][[1]]; Select[Range[200], AllTrue[ Divisors[#], odiousQ ] &] (* Amiram Eldar, Dec 09 2019 *) PROG (PARI) is(n)=fordiv(n, d, if(hammingweight(d)%2==0, return(0))); 1 \\ Charles R Greathouse IV, Mar 29 2013 CROSSREFS Cf. A001969, A093688. Sequence in context: A089559 A165741 A238989 * A190851 A325427 A336656 Adjacent sequences:  A093693 A093694 A093695 * A093697 A093698 A093699 KEYWORD nonn,base AUTHOR Jason Earls, May 16 2004 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 1 00:13 EDT 2021. Contains 346377 sequences. (Running on oeis4.)