The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A326826

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A326826

a(n) = (1/2) * Sum_{d|n} (sigma_1(d) + sigma_2(d)), where sigma_1 = A000203 and sigma_2 = A001157.
(history; published version)

#17 by Charles R Greathouse IV at Thu Sep 08 08:46:24 EDT 2022

PROG

(MAGMAMagma) [(1/2)*&+[DivisorSigma(1, d)+DivisorSigma(2, d):d in Divisors(n)]:n in [1..55]]; // Marius A. Burtea, Oct 20 2019

Discussion

Thu Sep 08

08:46

OEIS Server: https://oeis.org/edit/global/2944

#16 by Vaclav Kotesovec at Sat Dec 11 04:08:43 EST 2021

STATUS

editing

approved

#15 by Vaclav Kotesovec at Sat Dec 11 04:08:36 EST 2021

FORMULA

Sum_{k=1..n} a(k) ~ zeta(3)^2 * n^3 / 6. - Vaclav Kotesovec, Dec 11 2021

STATUS

approved

editing

#14 by Alois P. Heinz at Sun Oct 20 20:18:27 EDT 2019

STATUS

editing

approved

#13 by Alois P. Heinz at Sun Oct 20 20:18:23 EDT 2019

MAPLE

with(numtheory):

a:= n-> add(d*(d+1)*tau(n/d), d=divisors(n))/2:

seq(a(n), n=1..60); # Alois P. Heinz, Oct 20 2019

STATUS

proposed

editing

#12 by Marius A. Burtea at Sun Oct 20 14:53:16 EDT 2019

STATUS

editing

proposed

#11 by Marius A. Burtea at Sun Oct 20 14:51:31 EDT 2019

PROG

(MAGMA) [(1/2)*&+[DivisorSigma(1, d)+DivisorSigma(2, d):d in Divisors(n)]:n in [1..55]]; // Marius A. Burtea, Oct 20 2019

STATUS

proposed

editing

#10 by Michel Marcus at Sun Oct 20 14:43:31 EDT 2019

STATUS

editing

proposed

#9 by Michel Marcus at Sun Oct 20 14:43:28 EDT 2019

PROG

(PARI) a(n) = sumdiv(n, d, sigma(d)+sigma(d, 2))/2; \\ Michel Marcus, Oct 20 2019

STATUS

proposed

editing

#8 by Ilya Gutkovskiy at Sun Oct 20 14:06:50 EDT 2019

STATUS

editing

proposed