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A058267 An approximation to sigma_{1/2}(n): round( Sum_{ d divides n } sqrt(d) ). 2
1, 2, 3, 4, 3, 7, 4, 7, 6, 8, 4, 12, 5, 9, 9, 11, 5, 14, 5, 14, 10, 10, 6, 20, 8, 11, 11, 16, 6, 21, 7, 17, 12, 12, 12, 25, 7, 13, 13, 23, 7, 24, 8, 19, 19, 14, 8, 31, 11, 20, 14, 20, 8, 26, 14, 26, 15, 15, 9, 39, 9, 16, 21, 25, 15, 28, 9, 23, 16, 28, 9, 42, 10 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

map(round @ numtheory:-sigma[1/2], [$1..100]); # Robert Israel, Aug 18 2017

MATHEMATICA

f[n_] := Round@ DivisorSigma[1/2, n]; Array[f, 70] (* Robert G. Wilson v, Aug 17 2017 *)

PROG

(PARI) a(n) = round(sumdiv(n, d, sqrt(d))); \\ Michel Marcus, Aug 17 2017

CROSSREFS

Cf. A058266.

Sequence in context: A255046 A098596 A217536 * A048259 A324150 A198461

Adjacent sequences:  A058264 A058265 A058266 * A058268 A058269 A058270

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 08 2000

STATUS

approved

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Last modified September 18 09:40 EDT 2019. Contains 327168 sequences. (Running on oeis4.)