Is the sum of first $n$ factorials a square?
83862
How to prove that the number $1!+2!+3!+...+n!$ is never square?
135458
When is a sum of consecutive squares equal to a square?
119107
Is it true that $\sum_{k=3}^{n}\binom{n}{k}\binom{k}{3} = \binom{n}{3}\binom{n-3}{k-3}$?
20443
Calculate sum of squares of first $n$ odd numbers
65672
Proof of the summation $n!=\sum_{k=0}^n \binom{n}{k}(n-k+1)^n(-1)^k$?
114863
Representing a given number as the sum of two squares.
112644
The product of two numbers that can be written as the sum of two squares
19129
mathematical induction proof of a square vs factorial
58264
How to derive the formula for the sum of the first $n$ perfect squares?
67332
Sum of two squares modulo p
29799
Sum of four squares not a prime
120913
How would you write a non-recursive algorithm to calculate factorials?
143365
Is $\sum_{i=1}^{n-1}i=\binom{n}{2}$?
1379
Summation of $n^2x^n$ terms
48446
Summation involving a factorial: $1 + \sum_{j=1}^{n} j!j$
154082
Product of factorials divided by factorial to produce perfect square
142994
How to show $\sum_{i=1}^{n} \binom{i}{2}=\binom{n+1}{3}$?