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A227873 Sum of odious divisors of n. See A000069 for odious numbers.

%I A227873 #27 Apr 25 2025 22:37:45
%S A227873 1,3,1,7,1,3,8,15,1,3,12,7,14,24,1,31,1,3,20,7,29,36,1,15,26,42,1,56,
%T A227873 1,3,32,63,12,3,43,7,38,60,14,15,42,87,1,84,1,3,48,31,57,78,1,98,1,3,
%U A227873 67,120,20,3,60,7,62,96,29,127,14,36,68,7,70,129,1,15
%N A227873 Sum of odious divisors of n. See A000069 for odious numbers.
%C A227873 Sum of evil divisors of n is A000203(n) - a(n) = A260934(n). See A001969 for evil numbers.
%H A227873 Peter J. C. Moses, <a href="/A227873/b227873.txt">Table of n, a(n) for n = 1..10000</a>
%F A227873 a(n) = Sum_{d|n} A102392(d). - _Ridouane Oudra_, Apr 19 2025
%p A227873 A227873 := proc(n)
%p A227873     option remember ;
%p A227873     local a,d ;
%p A227873     a := 0 ;
%p A227873     for d in numtheory[divisors](n) do
%p A227873         if not isA001969(d) then
%p A227873             a := a+d ;
%p A227873         end if;
%p A227873     end do:
%p A227873     a ;
%p A227873 end proc:
%p A227873 seq(A227873(n),n=1..200) ; # _R. J. Mathar_, Aug 17 2022
%t A227873 Total[Select[Divisors@ #, OddQ@ First@ DigitCount[#, 2] &]] & /@ Range@ 72 (* _Michael De Vlieger_, Aug 04 2015 *)
%o A227873 (PARI) a(n) = sumdiv(n, d, d*(hammingweight(d) % 2)); \\ _Michel Marcus_, Aug 04 2015
%Y A227873 Cf. A000203, A227872, A000069, A001969, A212302, A260934, A010060, A102392.
%K A227873 nonn,base
%O A227873 1,2
%A A227873 _Vladimir Shevelev_, Oct 25 2013
%E A227873 More terms from _Peter J. C. Moses_
%E A227873 Minor changes. - _Wolfdieter Lang_, Aug 23 2015