Extension of factorial concept to negative numbers

A. M. Ibrahim
Notes on Number Theory and Discrete Mathematics, ISSN 1310–5132
Volume 19, 2013, Number 2, Pages 30–42
Full paper (PDF, 125 Kb)


Authors and affiliations

A. M. Ibrahim
Department of Mathematics,
Ahmadu Bello University, Zaria, Nigeria


This paper present a comparative study of the various types of positive factorial functions, among which include the conventional factorial, double factorial, quadruple factorial, superfactorial and hyperfactorial. Subsequently, an extension of the concepts of positive n! to negative numbers –n! is introduced. Based on this extension, a formulation of specific generalization cases for different forms of negative factorials are analyzed and presented.


  • Factorial
  • Negative factorial
  • Conventional factorials
  • Factorial functions


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Cite this paper

Ibrahim, A. M. (2013). Extension of factorial concept to negative numbers. Notes on Number Theory and Discrete Mathematics, 19(2), 30-42.

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