Journal of Integer Sequences, Vol. 27 (2024), Article 24.8.2

Two Combinatorial Interpretations of Rascal Numbers


Amelia Gibbs and Brian K. Miceli
One Trinity Place
Department of Mathematics
Trinity University
San Antonio, TX 78212
USA

Abstract:

The rascal triangle, a clever play on Pascal's triangle, was defined recursively by Anggoro et al., and has since been studied by many others. We assign two combinatorial interpretations to the elements of the rascal triangle, and these elements are dubbed the rascal numbers. The first combinatorial interpretation of the rascal numbers involves counting ascents in binary words; the second interpretation involves pattern avoidance in the ascent sequences studied by Duncan and Steingrímsson and is directly related to a more recent paper by Baxter and Pudwell. We provide many new Pascal-like formulas involving rascal numbers, and we conclude with a natural generalization of these numbers.


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(Concerned with sequences A051744 A077028.)


Received May 23 2024; revised versions received June 13 2024; November 5 2024; November 11 2024. Published in Journal of Integer Sequences, November 12 2024.


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