Klee's identity is the binomial sum
where
and
are nonnegative integers and
is a binomial coefficient,
taken to be 0 for
or
. The following array has rows indexed
by
, 1, ... and columns indexed by
, 1, ....
| 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 0 | 0 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| 0 | 0 | 0 | 4 | 0 | 0 | 0 | 0 | 0 | ||
| 0 | 0 | 0 | 6 | 1 | 0 | 0 | 0 | 0 | ||
| 0 | 0 | 0 | 0 | 4 | 6 | 0 | 0 | 0 | ||
| 0 | 0 | 0 | 0 | 1 | 15 | 1 | 0 | 0 | ||
| 0 | 0 | 0 | 0 | 0 | 20 | 8 | 0 | |||
| 0 | 0 | 0 | 0 | 0 | 15 | 28 | 1 |
(OEIS A092865)