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A284097 a(n) = Sum_{d|n, d=1 mod 5} d. 12
1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 12, 7, 1, 1, 1, 17, 1, 7, 1, 1, 22, 12, 1, 7, 1, 27, 1, 1, 1, 7, 32, 17, 12, 1, 1, 43, 1, 1, 1, 1, 42, 28, 1, 12, 1, 47, 1, 23, 1, 1, 52, 27, 1, 7, 12, 57, 1, 1, 1, 7, 62, 32, 22, 17, 1, 84, 1, 1, 1, 1, 72, 43, 1, 1, 1, 77, 12, 33, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

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

FORMULA

G.f.: Sum_{k>=0} (5*k + 1)*x^(5*k+1)/(1 - x^(5*k+1)). - Ilya Gutkovskiy, Mar 21 2017

MATHEMATICA

Table[Sum[If[Mod[d, 5] == 1, d, 0], {d, Divisors[n]}], {n, 80}] (* Indranil Ghosh, Mar 21 2017 *)

PROG

(PARI) for(n=1, 82, print1(sumdiv(n, d, if(Mod(d, 5)==1, d, 0)), ", ")) \\ Indranil Ghosh, Mar 21 2017

(Python)

from sympy import divisors

def a(n): return sum([d for d in divisors(n) if d%5==1]) # Indranil Ghosh, Mar 21 2017

CROSSREFS

Cf. A109697.

Cf. Sum_{d|n, d=1 mod k} d: A000593 (k=2), A078181 (k=3), A050449 (k=4), this sequence (k=5), A284098 (k=6), A284099 (k=7), A284100 (k=8).

Sequence in context: A140213 A331927 A285483 * A091258 A351568 A174544

Adjacent sequences:  A284094 A284095 A284096 * A284098 A284099 A284100

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Mar 20 2017

STATUS

approved

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Last modified October 6 10:56 EDT 2022. Contains 357263 sequences. (Running on oeis4.)