OFFSET
1,2
EXAMPLE
a(6) = floor(6/1) + floor(6/2) + floor(6/3) = 11.
MATHEMATICA
Table[If[n == 1, 1, Sum[Floor[n/i], {i, Floor[n/2]}]], {n, 80}] (* Wesley Ivan Hurt, Nov 26 2020 *)
PROG
(Python)
from math import isqrt
def A075995(n): return -(s:=isqrt(n))**2+(sum(n//k for k in range(1, s+1))<<1)-(n+1>>1) if n>1 else 1 # Chai Wah Wu, Oct 23 2023
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Sep 28 2002
EXTENSIONS
Name corrected by Wesley Ivan Hurt, Nov 26 2020
STATUS
approved