| 释义 |
Nonnegative Partial SumThe number of sequences with Nonnegative partial sums which can be formed from 1s and s (Bailey 1996,Brualdi 1992) is given by the Catalan Numbers. Bailey (1996) gives the number of Nonnegativepartial sums of 1s and s , , ..., , so that
 | (1) |
for all . The closed form expression is
 | (2) |
for ,
 | (3) |
for , and
 | (4) |
for . Setting then recovers the Catalan Numbers
 | (5) |
See also Catalan Number References
Bailey, D. F. ``Counting Arrangements of 1's and 's.'' Math. Mag. 69, 128-131, 1996.Brualdi, R. A. Introductory Combinatorics, 2nd ed. New York: Elsevier, 1992.
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