|
| |
|
|
A372217
|
|
a(n) is the number of distinct triangles whose sides do not pass through a grid point and whose vertices are three points of an n X n grid.
|
|
3
|
|
|
|
0, 1, 3, 8, 14, 36, 48, 100, 146, 232, 294, 502, 595, 938, 1143, 1433, 1741, 2512, 2826, 3911, 4458, 5319, 6067, 7976, 8728, 10750, 12076, 14194, 15671, 19510, 20669, 25349, 28115, 31716, 34697, 39467, 41894, 49766, 54046, 59948, 63951, 74818, 78216, 90773, 97220
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,3
|
|
|
LINKS
|
|
|
|
EXAMPLE
|
See the linked illustration for the terms a(1) = 1, a(2) = 3, a(3) = 8, a(4) = 14, a(5) = 36 and a(6) = 48.
|
|
|
MAPLE
|
S372217:=proc(n);
local s, x, u, v;
s:=0;
if n=1 then return 1 fi;
for x to n do
if gcd(x, n)=1 then
for u from x to n do
for v from 0 to n do
if gcd(u, v)=1 and gcd(u-x, n-v)=1 then
if u<n then s:=s+1;
elif v>=x then s:=s+1;
fi;
fi;
od;
od;
fi;
od;
return s;
end proc;
local i, a;
a:=0;
for i from 0 to n do
a:=a+S372217(i);
od;
return a;
end proc;
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
|
|
|
STATUS
|
approved
|
| |
|
|
