Volume 27, 2021

Volume 27, 2021, Number 1

• Published in March 2021
• 220 pages
• 21 original research papers

Volume 27, 2021, Number 2

• Published in June 2021
• 212 pages
• 21 original research papers, 1 book presentation

Volume 27, 2021, Number 3

• Published in September 2021
• 195 pages
• 19 original research papers, 1 book review

Volume 27, 2021, Number 4

• Published in December 2021
• 279 pages
• 26 original research papers, 1 corrigendum

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Author Index

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This volume of the International Journal “Notes on Number Theory and Discrete Mathematics”
is published with the financial support of the Bulgarian National Science Fund, Grant Ref. No.
KP-06-NP2/26/2020.