A116589 a(n) = Sum{sqrt(n) < i <= n} i - Sum{1 <= i < sqrt(n)} i.

0, 1, 4, 6, 9, 15, 22, 30, 36, 43, 54, 66, 79, 93, 108, 120, 133, 151, 170, 190, 211, 233, 256, 280, 300, 321, 348, 376, 405, 435, 466, 498, 531, 565, 600, 630, 661, 699, 738, 778, 819, 861, 904, 948, 993, 1039, 1086, 1134, 1176, 1219, 1270, 1322, 1375, 1429, 1484, 1540

Offset: 1

Author

N. J. A. Sloane, Apr 15 2006

Keywords

• nonn

Comments

Lim_{n->oo} a(n)/n^2 = 1/2. - Stefan Steinerberger, Apr 16 2006

Links

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

Crossrefs

Cf. A079667.

Programs

Mathematica

Table[Sum[i, {i, Ceiling[Sqrt[n]], n}]-Sum[i,{i,1,Floor[Sqrt[n]]}], {n, 1, 10}] (* Stefan Steinerberger, Apr 16 2006 *)