papers
Publications (58)
math.CO2002
Pattern avoidance in circular permutations
David Callan
math.CO2004
Some bijections for restricted Motzkin paths
David Callan
math.CO2011
A permutation pattern that illustrates the strong law of small numbers
David Callan
math.CO2014
A sign-reversing involution to count labeled lone-child-avoiding trees
David Callan
math.CO2007
A determinant of Stirling cycle numbers counts unlabeled acyclic single-source automata
David Callan
math.CO2008
Klazar trees and perfect matchings
David Callan
math.CO2011
Lagrange Inversion Counts $3\bar{5}241$-Avoiding Permutations
David Callan
math.CO2017
Enumeration of small Wilf classes avoiding 1324 and two other 4-letter patterns
David Callan, Toufik Mansour
math.CO2005
Some identities for the Catalan and Fine numbers
David Callan
math.CO2016
A note on a bijection for Schröder permutations
David Callan
math.CO2007
Bijections from Dyck paths to 321-avoiding permutations revisited
David Callan
math.CO2002
A recursive bijective approach to counting permutations containing 3-letter patterns
David Callan
math.CO2003
Counting stabilized-interval-free permutations
David Callan
math.CO2004
Two Bijections for Dyck Path Parameters
David Callan
math.CO2008
Pattern avoidance in "flattened" partitions
David Callan
math.CO2005
A Wilf equivalence related to two stack sortable permutations
David Callan
math.CO2003
A uniformly distributed parameter on a class of lattice paths
David Callan
math.CO2004
A combinatorial interpretation for a super-Catalan recurrence
David Callan
math.CO2009
A combinatorial survey of identities for the double factorial
David Callan
math.CO2006
A Combinatorial Interpretation of j/n {kn}\choose{n+j}
David Callan
math.CO2011
The number of \bar{2}413\bar{5}-avoiding permutations
David Callan
math.CO2005
On conjugates for set partitions and integer compositions
David Callan
math.CO2014
Restricted ascent sequences and Catalan numbers
David Callan, Toufik Mansour, Mark Shattuck
math.CO2005
Noncrossing partitions under rotation and reflection
David Callan, Len Smiley
math.CO2016
Five subsets of permutations enumerated as weak sorting permutations
David Callan, Toufik Mansour
math.CO2014
Another bijection for 021-avoiding ascent sequences
David Callan
math.CO2016
Restricted Stirling permutations
David Callan, Shi-Mei Ma, Toufik Mansour
math.CO2012
An identity for the central binomial coefficient
David Callan
math.CO2002
Jordan and Smith forms of Pascal-related matrices
David Callan
math.CO2011
The number of bar{3}bar{1}542-avoiding permutations
David Callan
math.CO2017
Enumeration of small Wilf classes avoiding 1342 and two other $4$-letter patterns
David Callan, Toufik Mansour
math.CO2012
An application of a bijection of Mansour, Deng, and Du
David Callan
math.CO2006
Permutations avoiding a nonconsecutive instance of a 2- or 3-letter pattern
David Callan
math.CO2016
Wilf classification of triples of 4-letter patterns
David Callan, Toufik Mansour, Mark Shattuck
math.CO2011
The Run Transform
David Callan, Emeric Deutsch
math.CO2014
Some combinatorial arrays related to the Lotka-Volterra system
Shi-Mei Ma, Toufik Mansour, David Callan
math.CO2006
Sierpinski's triangle and the Prouhet-Thue-Morse word
David Callan
math.CO2004
A combinatorial proof of Sun's "curious" identity
David Callan
math.CO2010
A bijection to count (1-23-4)-avoiding permutations
David Callan
math.CO2017
Bijections for Dyck paths with all peak heights of the same parity
David Callan
math.CO2013
A variant of Touchard's Catalan number identity
David Callan
math.CO2011
A combinatorial interpretation of the Catalan transform of the Catalan numbers
David Callan
math.CO2005
The 136th manifestation of C_n
David Callan
math.CO2016
A bijection for two sequences in OEIS
David Callan
math.CO2005
A combinatorial interpretation of the eigensequence for composition
David Callan
math.CO2006
A bijection on Dyck paths and its cycle structure
David Callan
math.HO2007
Cesaro's integral formula for the Bell numbers (corrected)
David Callan
math.CO2008
Sets, Lists and Noncrossing Partitions
David Callan
math.CO2017
Enumeration of permutations avoiding a triple of 4-letter patterns is all done
David Callan, Toufik Mansour, Mark Shattuck
math.CO2016
Revitalized automatic proofs: demonstrations
Tewodros Amdeberhan, David Callan, Hideyuki Ohtsuka +1
math.CO2008
Card deals, lattice paths, abelian words and combinatorial identities
David Callan
math.CO2008
Circular Digraph Walks, k-Balanced Strings, Lattice Paths and Chebychev Polynomials
Evangelos Georgiadis, David Callan, Qing-Hu Hou
math.CO2000
The eigenvectors of the right-justified Pascal triangle
David Callan
math.CO2012
Kreweras's Narayana number identity has a simple Dyck path interpretation
David Callan
math.CO2007
A combinatorial interpretation for the identity Sum_{k=0}^{n} binom{n}{k} Sum_{j=0}^{k} binom{k}{j}^{3}= Sum_{k=0}^{n} binom{n}{k}^{2}binom{2k}{k}
David Callan
math.CO2010
Flexagons yield a curious Catalan number identity
David Callan
math.CO2014
On permutations avoiding the dashed patterns 32-41 and 41-32
David Callan
math.CO2003
A combinatorial derivation of the number of labeled forests
David Callan