OFFSET
1,2
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
Sum_{k=1..n} a(k) ~ (2/3)*zeta(3/2) * n^(3/2). - Amiram Eldar, Jan 14 2023
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
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 08 2000
STATUS
approved