|
|
A334628
|
|
Total area of all distinct rectangles whose length and width are relatively prime and L + W = n.
|
|
0
|
|
|
0, 1, 2, 3, 10, 5, 28, 22, 42, 30, 110, 46, 182, 91, 140, 172, 408, 159, 570, 260, 420, 385, 1012, 380, 1050, 650, 1098, 770, 2030, 620, 2480, 1368, 1760, 1496, 2380, 1290, 4218, 2109, 2964, 2120, 5740, 1806, 6622, 3190, 4020, 3795, 8648, 3064, 8428, 4150, 6800, 5356, 12402
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,3
|
|
COMMENTS
|
Sum of the products of the parts in each partition of n into two relatively prime parts.
|
|
LINKS
|
|
|
FORMULA
|
a(n) = Sum_{i=1..floor(n/2)} [gcd(i,n-i) = 1] * i * (n-i), where [ ] is the Iverson bracket.
|
|
MATHEMATICA
|
Table[Sum[i*(n - i) KroneckerDelta[GCD[i, n - i], 1], {i, Floor[n/2]}], {n, 60}]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|