A248076 - OEIS

A248076

Partial sums of the sum of the 5th powers of the divisors of n: Sum_{i=1..n} sigma_5(i).

1, 34, 278, 1335, 4461, 12513, 29321, 63146, 122439, 225597, 386649, 644557, 1015851, 1570515, 2333259, 3415660, 4835518, 6792187, 9268287, 12572469, 16673621, 21988337, 28424681, 36677981, 46446732, 58699434, 73107634, 90873690, 111384840, 136555392

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OFFSET

1,2

LINKS

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

FORMULA

a(n) = Sum_{i=1..n} sigma_5(i) = Sum_{i=1..n} A001160(i).

a(n) ~ Zeta(6) * n^6 / 6. - Vaclav Kotesovec, Sep 02 2018

a(n) ~ Pi^6 * n^6 / 5670. - Vaclav Kotesovec, Sep 02 2018

a(n) = Sum_{k=1..n} (Bernoulli(6, floor(1 + n/k)) - 1/42)/6, where Bernoulli(n,x) are the Bernoulli polynomials. - Daniel Suteu, Nov 07 2018

a(n) = Sum_{k=1..n} k^5 * floor(n/k). - Daniel Suteu, Nov 08 2018

MAPLE

with(numtheory): A248076:=n->add(sigma[5](i), i=1..n): seq(A248076(n), n=1..50);

MATHEMATICA

Table[Sum[DivisorSigma[5, i], {i, n}], {n, 30}]

Accumulate[DivisorSigma[5, Range[30]]] (* Vaclav Kotesovec, Mar 30 2018 *)

PROG

(PARI) lista(nn) = vector(nn, n, sum(i=1, n, sigma(i, 5))) \\ Michel Marcus, Sep 30 2014

(Magma) [(&+[DivisorSigma(5, j): j in [1..n]]): n in [1..30]]; // G. C. Greubel, Nov 07 2018

(Python)

from math import isqrt

def A248076(n): return ((s:=isqrt(n))**3*(s+1)**2*(1-2*s*(s+1)) + sum((q:=n//k)*(12*k**5+q*(q**2*(q*(2*q+6)+5)-1)) for k in range(1, s+1)))//12 # Chai Wah Wu, Oct 21 2023

CROSSREFS

Cf. A001160 (sigma_5).

Cf. A024916: Partial sums of sigma(n) = A000203(n).

Cf. A064602: Partial sums of sigma_2(n) = A001157(n).

Cf. A064603: Partial sums of sigma_3(n) = A001158(n).

Cf. A064604: Partial sums of sigma_4(n) = A001159(n).

Sequence in context: A295917 A219927 A228284 * A301543 A252999 A229327

Adjacent sequences: A248073 A248074 A248075 * A248077 A248078 A248079

KEYWORD

nonn,easy

AUTHOR

Wesley Ivan Hurt, Sep 30 2014

STATUS

approved