Question

Considere a figura a seguir. Nessa figura, há duas circunferências de raios R1 = 3 e R2 = 2. A área destacada em azul vale *​

Answer 1

Step-by-step explanation:

In ascending order, each positive number $n$ appears $n$ times in a sequence $a_{n}$.

$1, 2, 2, 3, 3, 3, 4, 4, 4, 4, \cdots.$

Find the following value.

$\Huge\text{ \rightarrow\displaystyle\sum^{7}_{k=1}a_{10^{k}}. }$

#Challenge