A primitive sequence is a sequence of positive integers in which no term divides any other. Let be the set, where is a positive integer.
The numbers of primitive subsets of for , 2, ... are 2, 3, 5, 7, 13, 17, 33, 45, 73, 103, 205, 253,
... (OEIS A051026). For example, the seven
primitive subsets of are , , , , , , and .
be the set 
, where 
is a positive integer.
The numbers of primitive subsets of 
for 
, 2, ... are 2, 3, 5, 7, 13, 17, 33, 45, 73, 103, 205, 253,
... (OEIS A051026). For example, the seven
primitive subsets of 
are 
, 
, 
, 
, 
, 
, and 
.
of integers greater than 1, the
Erdős primitive set conjecture
concerns maximizing the weighted sum 
.
