Question

you are Vanni/ vabhav. you went to school after the covid wave over. express yourself in a diary sharing your experience of 1st day of school after long gap..​

Answer 1

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