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 A284344 Sum of the divisors of n that are not divisible by 10. 6

%I

%S 1,3,4,7,6,12,8,15,13,8,12,28,14,24,24,31,18,39,20,12,32,36,24,60,31,

%T 42,40,56,30,32,32,63,48,54,48,91,38,60,56,20,42,96,44,84,78,72,48,

%U 124,57,33,72,98,54,120,72,120,80,90,60,48,62,96,104,127,84,144

%N Sum of the divisors of n that are not divisible by 10.

%H Seiichi Manyama, <a href="/A284344/b284344.txt">Table of n, a(n) for n = 1..10000</a>

%F G.f.: Sum_{k>=1} k*x^k/(1 - x^k) - 10*k*x^(10*k)/(1 - x^(10*k)). - _Ilya Gutkovskiy_, Mar 25 2017

%t Table[Sum[Boole[Mod[d, 10]>0] d , {d, Divisors[n]}], {n, 100}] (* _Indranil Ghosh_, Mar 25 2017 *)

%o (PARI) for(n=1, 100, print1(sumdiv(n, d, ((d%10)>0)*d), ", ")) \\ _Indranil Ghosh_, Mar 25 2017

%o (Python)

%o from sympy import divisors

%o print [sum([i for i in divisors(n) if i%10>0]) for n in range(1, 101)] # _Indranil Ghosh_, Mar 25 2017

%Y Cf. A261776.

%Y Cf. Sum of the divisors of n that are not divisible by k: A046913 (k=3), A046897 (k=4), A116073 (k=5), A284326 (k=6), A113957 (k=7), A284341 (k=8), A116607 (k=9), this sequence (k=10).

%K nonn

%O 1,2

%A _Seiichi Manyama_, Mar 25 2017

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Last modified April 17 23:03 EDT 2021. Contains 343071 sequences. (Running on oeis4.)