of positive integers is called central if for every positive integer 
, the arithmetic mean of the first 
terms of the sequence is equal to 
of positive integers such that for every central sequence 
there are infinitely many positive integers 
.
be prime numbers such that their sum isn't divisible by 
.
positive integer quadruples satisfy:
Y by Adventure10, Mango247
Find all triangles 
for which 
is acute and the interior angle bisector of 
intersects the trisectors 
of the angle 
in the points 
respectively, such that 
, where 
is the foot of the altitude from 
on and 
is the midpoint of the side .
for which 
is acute and the interior angle bisector of 
intersects the trisectors 
of the angle 
in the points 
respectively, such that 
, where 
is the foot of the altitude from 
on and 
is the midpoint of the side .
,
be the feet of the altitude from 
and 
be the trisectors of the angle 
w
,
be the intersection points of the perpendicular bisector of side 
.
