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A284344 Sum of the divisors of n that are not divisible by 10. 6
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, 42, 40, 56, 30, 32, 32, 63, 48, 54, 48, 91, 38, 60, 56, 20, 42, 96, 44, 84, 78, 72, 48, 124, 57, 33, 72, 98, 54, 120, 72, 120, 80, 90, 60, 48, 62, 96, 104, 127, 84, 144 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..10000

FORMULA

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

MATHEMATICA

Table[Sum[Boole[Mod[d, 10]>0] d , {d, Divisors[n]}], {n, 100}] (* Indranil Ghosh, Mar 25 2017 *)

PROG

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

(Python)

from sympy import divisors

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

CROSSREFS

Cf. A261776.

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).

Sequence in context: A107749 A093811 A088000 * A168338 A034690 A069192

Adjacent sequences:  A284341 A284342 A284343 * A284345 A284346 A284347

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Mar 25 2017

STATUS

approved

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Last modified March 2 12:26 EST 2021. Contains 341750 sequences. (Running on oeis4.)