Cannot understand a solution to evaluating $C_{2}^{2000}+C_{5}^{2000}+C_{8}^{2000}+\cdots+C_{2000}^{2000}$
106441
Find the value of $\binom{2000}{2} + \binom{2000}{5} + \binom{2000}{8} + \cdots \binom{2000}{2000}$
87304
Solving for $x$ : $a^x+b^x=c$
69045
Solving this summation: $\sum_{i=1}^k i\cdot2^i$
14480
Proving $(P(AB))^2+(P(AB^c))^2+(P(A^cB))^2+(P(A^cB^c))^2\ge\frac{1}{4}$ for any events $A$ and $B$
76828
Evaluating $\sum_{i = 0}^{\lfloor n/2 \rfloor} {n \choose 2i}p^{2i}(1 - p)^{n - 2i}$
72360
Find the value of $a^{2m}+a^m+{1\over a^m}+{1\over a^{2m}}$
17390
Find $LK_1^2 + LK_2^2 + \dots + LK_{11}^2$.
41840
How do I evaluate this sum(involving the floor function)?
33105
Find the value of $a^2-b^2+c^2$
30851
Find the summation $\frac{1}{1!}+\frac{1+2}{2!}+\frac{1+2+3}{3!}+ \cdots$
57846
Multiplicative inverse in $\operatorname{GF}(2^8)$?
61580
Calculating the determinant gives $(a^2+b^2+c^2+d^2)^2$?
8589
$\sqrt[b_1]{a_1}+\sqrt[b_2]{a_2}+\cdots+\sqrt[b_k]{a_k}$ not an integer
49443
What is the value of $\arctan(1/2)+\arctan(1/5)+\arctan(1/8)$?
84147
Evaluating $\sum_{n=1}^\infty \frac{2^{2n-1}}{5^{n+1}}$
18903
Finding solutions to equation of the form $1+x+x^{2} + \cdots + x^{m} = y^{n}$
67666
show that $a^2+b^2+c^2+2abc+3\ge (1+a)(1+b)(1+c)$