Number Theory

Is e Normal?
Identities for Linear Recurring Sequences
The Half-Totient Tree
Symmetric Pseudoprimes
Primes of the Form 2^(k-1) + k
Limit Cycles of xy (mod x+y)
A Knot of Congruences
Rounding Up to PI
Fermat's Last Theorem for Cubes
Digit Reversal Sums Leading to Palindromes
Self-Similar Reverse-Sum Sequences
The Sum of the Prime Factors of N
Sequence Partitionable Into Powers of 2 or 3
Iterated Sum-of-Digits Function
If ab+1, ac+1, bc+1 are squares,...
Zeisel Numbers
The Jewel of Arithmetic: Quadratic Reciprocity
Highly Wilsonian Primes
Congruences on 4th Order Recurrences
Quadratic Congruences
Squares in Arithmetic Progression (mod p)
Numeri Idonei
Sequences With No Arithmetic Progressions
A Primality Criterion
Can n Divide !n ?
Periods of Fibonacci Sequences mod m
Diophantine Walk-a-thon
Barlow's Observation
Divisors of an n-term Geometric Series
More Results on the Form xy (mod x+y)
Sums of Three Cubes
Congruences Involving the Totient Function
A Conjecture On The Fermat Function
Smith Numbers and Rhonda Numbers
Infinitely Many Rhondas
Why z Is Not a Prime Power in z^p = x^p + y^p
Summations and Recurrences
Evidence for Goldbach
On the Equation n! + 1 = m^2
No Four Squares In Arithmetic Progression
Minimum Difference Function
Gauss' Lemma Without Divisibility Arguments
Product Divisible By Sum of Squares
Lucas and Perrin Pseudoprimes
Pseudoprimes For x^2 - 4x - 9
On x^2 + y^2 = z^4, x + y = w^2
Exponential Iteration
Sums of Consecutive Nth Powers Equal to an Nth Power
On Case 1 of Fermat's Last Theorem
A Mersenne Coincidence
Coprime Partitions
The 450 Pound Problem (x^3 + y^3 = 6z^3)
Is This a Prime?
Reverse Greed for Unit Fractions
Sum of Divisors Equals a Power of 2
Sublime Numbers
On x^2 + y^3 = z^6
A Method Of Factoring Based On 1/N
The Distribution of Perfection
Fermat's Last Theorem for Quadratic Integers
Square Triangular Numbers
Powers Differing By 1 (Catalan)
Primes In the Decimal Expansion of Pi
Recurrences and Pell Equations
In Defense of Base-Related Problems
On x^3 - x + y^3 - y = z^3 - z
On the Density of Some Exceptional Primes
Double Equations from Triangles in Squares
Differently Perfect
A Special Property of 151
Simple Complex Quadratic Fields
The Euclidean Algorithm
Casting Out Nines
Detecting Squares
Numbers Expressible As (a^2 - 1)(b^2 - 1)
Concordant Forms
On Even Fibonacci Numbers
Solving Magic Squares
On m = sqrt(sqrt(n) + sqrt(kn+1))
Unit Fractions and Fibonacci
Cyclic Divisibility
Waring's Problem
Testing For Prime Repunits
The 2 Ohm Problem
Reflective and Cyclic Sets of Primes
Simple BASIC Program for Pseudoprimes
Unit Fraction Partitions
Given primes p,q, Find Pseudoprime pqr
N = (x^2 + y^2)/(1+xy) Is A Square
Perrin's Sequence
Proof of Generalized Little Theorem of Fermat
Minimizing the Denominators in Unit Fraction Expansions
On General Palindromic Numbers
Farey Series
Pythagorean Graphs
Progress on Sum of Prime Divisors Function
Series Within Parallel Resistor Circuits
Sequences Based On Continued Fraction For PI
Smallest Quadrilateral With Distinct Integer Sides
Schizophrenic Numbers
Coherent Arrays of Squares
Anti-Carmichael Pairs
Magic Square of Squares
Orthomagic Square of Squares
Automedian Triangles and Magic Squares
Continued Fractions and Characteristic Recurrences
One In The Chamber
On a^4 + b^3 = c^2
On a Unit Fraction Question of Erdos and Graham
Odd, Greedy, and Stubborn (Unit Fractions)
Average of Sigma(n)/n
Lucas's Primality Test With Factored N-1
Highly Heronian Ellipses
How Leibniz Might Have Anticipated Euler
Wagon Trains and Sticky Wickets
Factoring Zeta
Accidental Melodies
Some Properties of the Lucas Sequence (2,4,14,52,194,...)
Four Squares From Three Numbers
Meandering Convergence of a Dirichlet Series
Geodesic Diophantine Boxes
Least Significant Non-Zero Digit of n!
Discordance Impedes Square Magic
No Four Rectangles In Line?