Timeline for A double grading of catalan numbers
Current License: CC BY-SA 3.0
2 events
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| May 25, 2013 at 23:48 | comment | added | F Castillo | In terms of sequences $a_1,a_2,\cdots,a_{n−1}$ such that $a_0=0$ and $a_{i+1}≤a_i+1$. The bijection should be between sequences with $a_m=m$ and $a_{m+1}\leq m$ and sequences with $m$ special elements $a_s $such that $a_k\leq a_s$ for $k<s$ and $a_s\neq a_l$ for$s<l$. The bijection should preserve the number of zeros. | |
| May 25, 2013 at 22:26 | history | answered | F Castillo | CC BY-SA 3.0 |