OFFSET
1,5
FORMULA
a(n) = Sum_{j=1..floor(n/3)} Sum_{i=j..floor((n-j)/2)} (1 - ceiling((n-i-j)/j) + floor((n-i-j)/j)).
MATHEMATICA
a[n_] := Sum[1 - Ceiling[(n - i - j)/j] + Floor[(n - i - j)/j], {j, 1, Floor[n/3]}, {i, j, Floor[(n - j)/2]}]; Array[a, 100] (* Amiram Eldar, Oct 22 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Oct 21 2021
STATUS
approved