A166381 - OEIS

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

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OFFSET

1,2

LINKS

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

FORMULA

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

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}]

CROSSREFS

Column sums of A166373.

Sequence in context: A049554 A019398 A086513 * A083723 A294866 A045947

Adjacent sequences: A166378 A166379 A166380 * A166382 A166383 A166384

KEYWORD

nonn,easy

AUTHOR

Christopher Hunt Gribble, Oct 13 2009

STATUS

approved