A153817 a(n)=Sum_{k=1..n} floor((n*k)/(n+k)).

0, 1, 2, 4, 6, 10, 13, 18, 22, 28, 33, 42, 48, 57, 65, 74, 83, 95, 105, 118, 130, 142, 155, 171, 185, 200, 216, 232, 248, 270, 286, 307, 325, 345, 365, 390, 409, 433, 454, 480, 502, 532, 555, 583, 610, 636, 665, 695, 723, 753, 784, 814, 847, 880, 913, 947, 981

Offset: 1

Author

Ctibor O. Zizka, Jan 02 2009

Keywords

• easy
• nonn

Crossrefs

Cf. A000005, A006218, A118014, A153818.

Programs

Maple

A153817 := proc(n) add(floor(n*k/(n+k)), k=1..n) ; end: seq(A153817(n),n=1..100) ; # R. J. Mathar, Feb 21 2009

Mathematica

Table[Sum[Floor[n*k/(n + k)], {k, 1, n}], {n, 1, 100}] (* Vaclav Kotesovec, May 28 2021 *)

Formula

a(n) ~ (1 - log(2)) * n^2. - Vaclav Kotesovec, May 28 2021

Extensions

More terms from R. J. Mathar, Feb 21 2009