**26**(1999)

## Editorial Board:Péter Kiss, Ferenc Mátyás ## Technical Editor:Miklós Hoffmann, Tibor Tómács |

## Content

### Research papers:

Perfect numbers concerning Fibonacci sequence

by Bui Minh Phong

Pages: 3–8

On a problem connected with matrices over *Z*_{3}

by Aleksander Grytczuk

Pages: 9–12

Studying and improving linear mappings by artificial neural networks

by Emőd Kovács

Pages: 13–18

On polynomial values of the product of the terms of linear recurrence sequences

by Kálmán Liptai

Pages: 19–23

On a problem concerning perfect powers in linear recurrences

by Péter Kiss

Pages: 25–30

An associative algorithm

by Gyula Maksa

Pages: 31–38

On the associativity of algorithms

by Tibor Farkas

Pages: 39–47

Recursive formulae for special continued fraction convergents

by Ferenc Mátyás

Pages: 49–55

A Sehgal’s problem

by Bertalan Király

Pages: 57–73

A moment inequality for the maximum partial sums with a generalized superadditive structure

by Tibor Tómács

Pages: 75–79

On the shape modification of parametric cubic arcs

by Imre Juhász

Pages: 81–86

Exponential stability of regular linear systems on Banach spaces

by Tran Thi Loan

Pages: 87–98

On the fix point of order *2 ^{n}* (in Hungarian)

by Bálint Szepessy

Pages: 99–103

### Methodological papers:

Matematikafeladatok érdekessége, nehézsége a tanulók szemszögéből (in Hungarian)

by Orosz Gyuláné

Pages: 107–114

Problems and mistakes of the teaching of mathematical analysis I. (in Hungarian)

by Mihály Rados

Pages: 115–120

Egy felmérés tanulságai (in Hungarian)

by Sashalminé Kelemen Éva

Pages: 121–126