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

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, May 14 2010

Keywords

• nonn

Links

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

Programs

Haskell

a177853 n = a177853_list !! (n-1)
a177853_list = scanl1 (+) a018805_list
-- Reinhard Zumkeller, May 04 2014

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 *)

Formula

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