A294628 a(n) = 8*(sigma(n) - n + (1/2)).

4, 12, 12, 28, 12, 52, 12, 60, 36, 68, 12, 132, 12, 84, 76, 124, 12, 172, 12, 180, 92, 116, 12, 292, 52, 132, 108, 228, 12, 340, 12, 252, 124, 164, 108, 444, 12, 180, 140, 404, 12, 436, 12, 324, 268, 212, 12, 612, 68, 348, 172, 372, 12, 532, 140, 516, 188, 260, 12, 868, 12, 276

Offset: 1

Author

Omar E. Pol, Nov 05 2017

Keywords

• nonn

Links

• Muniru A Asiru, Table of n, a(n) for n = 1..2000

Crossrefs

Partial sums give A294629.

Cf. A001065, A017113, A235796, A237593, A239050, A294015, A294016, A294017, A294630.

Programs

GAP

List([1..10^5],n->8*(Sigma(n)-n+(1/2))); # Muniru A Asiru, Mar 04 2018

Maple

with(numtheory): seq(sigma(8*n-1)/8, n=1..10^3); # Muniru A Asiru, Mar 04 2018

Mathematica

a[n_] := 8 (DivisorSigma[1, n] - n) + 4; Array[a, 62] (* Robert G. Wilson v, Dec 12 2017 *)

Formula

a(n) = 4*A294015(n).

a(n) = 8*(A001065(n) + (1/2)).

a(n) = 8*(A000203(n) - n + (1/2)).

a(n) = A239050(n) - 4*A235796(n).

a(n) = A017113(n-1) - 8*A235796(n).