As you probably know, Google Blogger platform provide excellent Javscript code inside raw Templates but unfortunately, there's now support for the Script tag inside a post.
So here's a quick and easy way to do publish a post on blogspot contain the forbiddent script tag.
Blogger will throw an error as in the screen capture. Ignore that error. Just beneath the error line is a checkbox that says "Stop showing HTML errors for this post" - tick the checkbox and click publish again. Wow. The post in now online.
While this hack can also be used to embed Adsense code anywhere inside the blog posts, I would not suggest doing so because if in future, Google decides to modify the Adsense code, you'll have to revisit all these blogger posts to update the Adsense code.