1
The number of squares with vertices coming from the vertices of the $n$-dimensional hypercube $\{0,1\}^n$ is given by $$
2^{n-3}\sum_{j=1}^{n} \binom{n}{j}\binom{n-j}{j}.
$$
The $0$-indexed sequence begins $0, 0, 1, 6, 36, 200, 1120, 6272, 35392, 200832, 1145856, \dots$.
For example, when $n=4$, ...
-1
Resolved: The tags have been removed.
The tags bijectivity, injectivity and surjectivity have been created not so long ago (they are still in the list of new tags.) A natural question is what to do with these tags.
So far the questions about these topics were typically tagged functions and...
2
The number of squares with vertices coming from the vertices of the $n$-dimensional hypercube $\{0,1\}^n$ is given by $$
2^{n-3}\sum_{j=1}^{n} \binom{n}{j}\binom{n-j}{j}.
$$
The $0$-indexed sequence begins $0, 0, 1, 6, 36, 200, 1120, 6272, 35392, 200832, 1145856, \dots$.
For example, when $n=4$, ...
