A166381 a(n) = Sum_{j>n} floor(n^2/j).

0, 2, 7, 17, 31, 52, 76, 108, 146, 191, 242, 301, 364, 437, 518, 605, 700, 804, 914, 1034, 1160, 1295, 1438, 1594, 1751, 1921, 2098, 2288, 2483, 2688, 2898, 3119, 3350, 3593, 3845, 4103, 4369, 4647, 4937, 5234, 5540, 5854, 6178, 6512, 6859

Offset: 1

Author

Christopher Hunt Gribble, Oct 13 2009

Keywords

• nonn
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000

Crossrefs

Column sums of A166373.

Programs

Maple

A166381 := proc(n)
    add( floor(n^2/j),j=n+1..n^2) ;
end proc: # R. J. Mathar, Jul 21 2015

Mathematica

Table[Sum[Floor[n (n - i)/i], {i, n}], {n, 100}]

Formula

a(n) = Sum_{i=1..n} floor(n*(n-i)/i). - Wesley Ivan Hurt, Jan 30 2016