Maximise sum, Number theory
32858
If a,b,c,d are positive integers with a sum of 63, what is the maximum value of ab + bc + cd ? (By using calculus to solve it))
104309
Pigeon-Hole Principle Common Sum
103840
Calculate $\sum_{k=1}^n k2^{n-k}$
143374
Elegant proof that maximum of sums is, at most, sum of maximums
61417
List of numbers giving a particular sum
41876
Finding an asymptotic for the sum $\sum_{p\leq x}p^m$
40784
$\sum_{k=m}^{n}(-1)^k\binom{n}{k}\binom{k}{m}=0, n>m\geq 0$
11359
Determine the Set of a Sum of Numbers
57986
Sum of products of combinatorials
20285
How to sum over primes
93572
How to determine if $n (n \geq 2)$ given numbers can be summed up to a certain number?
147766
Sum of Permutations from 0 to n
159010
Solve sum with indices
13750
Position the limits of Sum
57092
Sum of radicals greater than 1
122534
Show that $\sum (-1)^{n+1}/n$ = $k$ can be expanded to a sum with $ 1 - 1/2 + 1/3 + 1/5 - 1/4 +1/7 + 1/9 - 1/6 + ....$ which is $3k/2$
31267
Sum of all primes under 2 million