OFFSET
1,4
COMMENTS
Partial sums of A327166. - Rémy Sigrist, Jul 23 2022
LINKS
R. Balasubramanian and K. Ramachandra, On the number of integers n such that nd(n)<=x, Acta Arith., 49 (1988), 313-322.
Vaclav Kotesovec, Plot of a(n) / (n/sqrt(log(n))) for n = 1..10^7
FORMULA
a(n) is asymptotic to C*n/sqrt(log(n)) for a suitable constant C > 0.
MATHEMATICA
Table[Sum[If[k*DivisorSigma[0, k] <= n, 1, 0], {k, 1, n}], {n, 1, 100}] (* Vaclav Kotesovec, Jul 23 2022 *)
PROG
(PARI) a(n)=sum(k=1, n, if(k*numdiv(k)<=n, 1, 0))
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Jul 22 2022
STATUS
approved