Is **now** available **here** !

This weblication is written by PEN team and contributors:

**Alexander Remorov** (Canada),

**Darij Grinberg** (Germany),

**Harun Siljak** (Bosnia and Herzegovina),

**Mari****n Misur** (Croatia).

We also need to thank two Editors-in-Chief:

**Daniel Kohen** (Argentina) and **Cosmin Pohoata** (Romania).

**Here goes the table of contents: **

1 Problems 1

2 Articles 3

2.1 Three Ways to Attack a Functional Equation . . . . . . . . . . . . . . . . . . . . . 3

2.2 A Generalization of an Identity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3 Minimum prime divisors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.4 Dierent Approaches to an Intuitive Problem . . . . . . . . . . . . . . . . . . . . . 15

2.5 Exponential Congruence Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.6 Using Quadratic Residues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2.7 A Hidden Divisibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

2.8 Fractions Mod p and Wolstenholme’s theorem . . . . . . . . . . . . . . . . . . . . . 29

2.9 A binomial sum divisible by primes . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.10 Sequences of Consecutive Integers . . . . . .

1 Problems 1

2 Articles 3

2.1 Three Ways to Attack a Functional Equation . . . . . . . . . . . . . . . . . . . . . 3

2.2 A Generalization of an Identity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3 Minimum prime divisors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.4 Dierent Approaches to an Intuitive Problem . . . . . . . . . . . . . . . . . . . . . 15

2.5 Exponential Congruence Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.6 Using Quadratic Residues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2.7 A Hidden Divisibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

2.8 Fractions Mod p and Wolstenholme’s theorem . . . . . . . . . . . . . . . . . . . . . 29

2.9 A binomial sum divisible by primes . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.10 Sequences of Consecutive Integers . . . . . .