A260934 - OEIS

%I #12 Nov 13 2019 10:12:53

%S 0,0,3,0,5,9,0,0,12,15,0,21,0,0,23,0,17,36,0,35,3,0,23,45,5,0,39,0,29,

%T 69,0,0,36,51,5,84,0,0,42,75,0,9,43,0,77,69,0,93,0,15,71,0,53,117,5,0,

%U 60,87,0,161,0,0,75,0,70

%N Sum of evil divisors of n. For evil numbers see A001969.

%C a(n) = 0 if there is no evil divisor.

%H Amiram Eldar, <a href="/A260934/b260934.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A000203(n) - A227873(n). - _Vladimir Shevelev_, Oct 25 2013.

%e a(6) = A000203(6) - A227873(6) = 12 - 3 = 9.

%t Total[Select[Divisors@ #, EvenQ@ First@ DigitCount[#, 2] &]] & /@ Range@ 65 (* _Michael De Vlieger_, Aug 04 2015 *)

%Y Cf. A001969, A227873, A000203.

%K nonn,base,easy

%O 1,3

%A _Juri-Stepan Gerasimov_, Aug 04 2015

%E Edited by _Wolfdieter Lang_, Aug 23 2015