|
|
A226323
|
|
Number of ordered pairs (i,j) with |i| * |j| <= n and gcd(i,j) <= 1.
|
|
1
|
|
|
1, 9, 17, 25, 33, 41, 57, 65, 73, 81, 97, 105, 121, 129, 145, 161, 169, 177, 193, 201, 217, 233, 249, 257, 273, 281, 297, 305, 321, 329, 361, 369, 377, 393, 409, 425, 441, 449, 465, 481, 497, 505, 537, 545, 561, 577, 593, 601, 617, 625, 641, 657, 673, 681, 697
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
Note that gcd(0,m) = m for any m.
|
|
LINKS
|
|
|
FORMULA
|
|
|
MAPLE
|
with(numtheory):
a:= n-> `if`(n=0, 1, 5+4*add(mobius(k)^2*floor(n/k), k=1..n)):
|
|
MATHEMATICA
|
f[n_] := Length[Complement[Union[Flatten[Table[If[Abs[i]*Abs[j] ≤ n && GCD[i, j] ≤ 1, {i, j}], {i, -n, n}, {j, -n, n}], 1]], {Null}]]; Table[f[n], {n, 0, 100}]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|