Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A combinatorial interpretation of the Catalan transform of the Catalan
  numbers   The Catalan transform of a sequence (a_{n})_{n>=0} is the sequence
(b_{n})_{n>=0} with b_{n} = Sum[k/(2n-k) (2n-k)-choose-(n-k) a_{k},k=0..n].
Here we show that the Catalan transform of the Catalan numbers has a simple
interpretation: it counts functions f:[1,n] -> [1,n] satisfying the condition
that, for all i<j, f(j)-(j-i) is not in the interval [1,f(i)-1].

1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom