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A024917 a(n) = Sum_{k=2..n} k*floor(n/k). 2
2, 5, 11, 16, 27, 34, 48, 60, 77, 88, 115, 128, 151, 174, 204, 221, 259, 278, 319, 350, 385, 408, 467, 497, 538, 577, 632, 661, 732, 763, 825, 872, 925, 972, 1062, 1099, 1158, 1213, 1302, 1343, 1438, 1481, 1564, 1641, 1712, 1759, 1882, 1938, 2030, 2101, 2198, 2251 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Table of n, a(n) for n=2..53.

FORMULA

a(n) = A024916(n) - n, for n>=2. - Paolo P. Lava, Jan 08 2013

G.f.: (1/(1 - x)) * Sum_{k>=2} k*x^k/(1 - x^k). - Ilya Gutkovskiy, Sep 02 2019

MATHEMATICA

Table[Sum[k*Floor[n/k], {k, 2, n}], {n, 2, 60}] (* Harvey P. Dale, Mar 13 2015 *)

PROG

(MAGMA) [&+[k*Floor(n/k): k in [2..n]]: n in [2..55]]; // Bruno Berselli, Jan 08 2012

(PARI) a(n) = sum(k=2, n, k*floor(n/k)); \\ Michel Marcus, Sep 02 2019

CROSSREFS

Cf. A002541, A024916.

Sequence in context: A080156 A082083 A287558 * A081402 A281023 A118660

Adjacent sequences:  A024914 A024915 A024916 * A024918 A024919 A024920

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified January 25 07:25 EST 2020. Contains 331241 sequences. (Running on oeis4.)