Where did we find Ramanujan's series for the exponential integral?

According to Wikipedia, the following series for the exponential integral

$$\operatorname{Ei}(x) = \gamma \ln x + \exp{\frac{x}{2}} \sum_{n=1}^{\infty} \frac{(-1)^{n-1}x^n}{n! 2^{n-1}} \sum_{k=0}^{\lfloor \frac{n-1}{2} \rfloor} \frac{1}{2k+1}$$

was found by Ramanujan. Was this among the results found in his notebooks by either Littlewood or Hardy?