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Sum of odious divisors of n. See A000069 for odious numbers.
5

%I #24 Aug 17 2022 12:30:14

%S 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 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 67,120,20,3,60,7,62,96,29,127,14,36,68,7,70,129,1,15

%N Sum of odious divisors of n. See A000069 for odious numbers.

%C Sum of evil divisors of n is A000203(n) - a(n) = A260934(n). See A001969 for evil numbers.

%H Peter J. C. Moses, <a href="/A227873/b227873.txt">Table of n, a(n) for n = 1..10000</a>

%p A227873 := proc(n)

%p option remember ;

%p local a,d ;

%p a := 0 ;

%p for d in numtheory[divisors](n) do

%p if not isA001969(d) then

%p a := a+d ;

%p end if;

%p end do:

%p a ;

%p end proc:

%p seq(A227873(n),n=1..200) ; # _R. J. Mathar_, Aug 17 2022

%t Total[Select[Divisors@ #, OddQ@ First@ DigitCount[#, 2] &]] & /@ Range@ 72 (* _Michael De Vlieger_, Aug 04 2015 *)

%o (PARI) a(n) = sumdiv(n, d, d*(hammingweight(d) % 2)); \\ _Michel Marcus_, Aug 04 2015

%Y Cf. A000203, A227872, A000069, A001969, A212302, A260934.

%K nonn,base

%O 1,2

%A _Vladimir Shevelev_, Oct 25 2013

%E More terms from _Peter J. C. Moses_

%E Minor changes. - _Wolfdieter Lang_, Aug 23 2015