UnsolvedMath
Problems
Categories
Sets
Search
Unsolved Problems
Showing 1-1 of 1 problems
Difficulty Level
All Levels
L1: Tractable
L2: Intermediate
L3: Advanced
L4: Expert
L5: Millennium Prize
Category
All Categories
Number Theory
Combinatorics
Graph Theory
Algebra
Algebraic Geometry
Geometry
Topology
Analysis
Partial Differential Equations
Set Theory
Computer Science
Mathematical Physics
Problem Set
All Sets
Millennium Prize Problems
Hilbert's 23 Problems
Ben Green's 100 Open Problems
DARPA's 23 Mathematical Challenges
Smale's Problems
Landau's Problems
Status
All Status
Open
Solved
LAN-004
Open
Landau's Fourth Problem: Primes of the Form n² + 1
Are there infinitely many primes of the form $n^2 + 1$?...
L4
Number Theory
398
22