A339217 a(n) = Sum_{k=1..n} floor((2*n-k)/k).

0, 1, 4, 8, 12, 17, 23, 27, 34, 40, 46, 52, 60, 65, 73, 81, 87, 93, 104, 108, 118, 126, 132, 140, 150, 157, 165, 173, 183, 189, 201, 205, 216, 226, 232, 242, 254, 258, 268, 278, 288, 295, 307, 313, 323, 335, 343, 349, 363, 369, 382, 390, 398, 408, 420, 428, 440, 448, 456, 464, 482

Offset: 0

Author

Wesley Ivan Hurt, Dec 22 2020

Keywords

• nonn
• easy

Crossrefs

Cf. A002541, A153485, A279847, A338991, A339370.

Programs

Mathematica

Table[Sum[Floor[(2 n - i)/i], {i, n}], {n, 0, 60}]

PARI

a(n) = sum(k=1, n, (2*n-k)\k); \\ Michel Marcus, Dec 22 2020

Formula

From Vaclav Kotesovec, Dec 23 2020: (Start)

For n>0, a(n) = 2*A006218(n) + A075989(n) - n.

a(n) ~ 2*n * (log(2*n) + 2*gamma - 2), where gamma is the Euler-Mascheroni constant A001620. (End)