**Volume 2** ▶ Number 1 ▷ Number 2 ▷ Number 3 ▷ Number 4

**Preface**

*Editorial. Page 1*

Aldo Peretti

**On one generalization of the Fibonacci sequence. Part IV: Multiplicity roots of the characteristic equation**

*Original research paper. Pages 3–7*

Peter G. Georgiev and Krassimir T. Atanassov

**On one generalization of the Fibonacci sequence. Part V: Some examples**

*Original research paper. Pages 8–13*

Peter G. Georgiev and Krassimir T. Atanassov

**On one generalization of the Fibonacci sequence. Part VI: Some other examples**

*Original research paper. Pages 14–17*

Peter G. Georgiev and Krassimir T. Atanassov

**A combinatorial summation identity for polygonal numbers**

*Original research paper. Pages 18–20*

R. S. Melham and A. G. Shannon

**A set-method for representation of the solutions of some Diophantine equations and some of its applications**

*Original research paper. Pages 21–26*

Krassimir T. Atanassov

**On the solutions of t_{m} + t_{n} = t_{x} and t_{m} − t_{n} = t_{y}**

*Original research paper. Pages 27–29*

Krassimir T. Atanassov

**One property of ψ function**

*Original research paper. Pages 30–31*

Vassia K. Atanassova

**A generalization of an arithmetic function**

*Original research paper. Pages 32–33*

Krassimir T. Atanassov

**Two extremal problems**

*Original research paper. Pages 34–37*

Krassimir T. Atanassov

**Four extremal problems**

*Original research paper. Pages 38–40*

Krassimir T. Atanassov

**The numbers which cannot be values of Euler’s function ***φ*

*Original research paper. Pages 41–48*

Mladen Vassilev-Missana

**Remarks on prime numbers**

*Original research paper. Pages 49–51*

Krassimir T. Atanassov

**New integer functions related to ϕ and σ functions. V**

*Original research paper. Pages 52–55*

Krassimir T. Atanassov

**Remark on set F _{A}**

*Original research paper. Pages 56–57*

Krassimir T. Atanassov

**Two variants of the concept “Logarithmic progression”**

*Original research paper. Pages 58–60*

Krassimir T. Atanassov