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A227873
Sum of odious divisors of n. See A000069 for odious numbers.
5
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, 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, 67, 120, 20, 3, 60, 7, 62, 96, 29, 127, 14, 36, 68, 7, 70, 129, 1, 15
OFFSET
1,2
COMMENTS
Sum of evil divisors of n is A000203(n) - a(n) = A260934(n). See A001969 for evil numbers.
LINKS
MAPLE
A227873 := proc(n)
option remember ;
local a, d ;
a := 0 ;
for d in numtheory[divisors](n) do
if not isA001969(d) then
a := a+d ;
end if;
end do:
a ;
end proc:
seq(A227873(n), n=1..200) ; # R. J. Mathar, Aug 17 2022
MATHEMATICA
Total[Select[Divisors@ #, OddQ@ First@ DigitCount[#, 2] &]] & /@ Range@ 72 (* Michael De Vlieger, Aug 04 2015 *)
PROG
(PARI) a(n) = sumdiv(n, d, d*(hammingweight(d) % 2)); \\ Michel Marcus, Aug 04 2015
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Vladimir Shevelev, Oct 25 2013
EXTENSIONS
More terms from Peter J. C. Moses
Minor changes. - Wolfdieter Lang, Aug 23 2015
STATUS
approved