A177853 - OEIS

A177853

Partial sums of A018805.

1, 4, 11, 22, 41, 64, 99, 142, 197, 260, 343, 434, 549, 676, 819, 978, 1169, 1372, 1611, 1866, 2145, 2444, 2787, 3146, 3545, 3968, 4427, 4910, 5449, 6004, 6619, 7266, 7953, 8672, 9439, 10230, 11093, 11992, 12939, 13918, 14977, 16060, 17227, 18434, 19689

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OFFSET

1,2

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

FORMULA

a(n) ~ 2*n^3/Pi^2. - Vaclav Kotesovec, Sep 14 2021

MATHEMATICA

s=0; lst={}; Do[c={}; Do[Do[AppendTo[c, b/a], {b, z}], {a, z}]; AppendTo[lst, s+=Length[Union@c]], {z, 66}]; lst

Accumulate[Accumulate[2*EulerPhi[Range[60]]]-1] (* Harvey P. Dale, Nov 23 2019 *)

PROG

(Haskell)