There is a calculated column 'trick' where you return a number type but use regular string concatenation and an html 'a' tag and the item will show up for you as a link
="<a href='https://www.google.com?q='"&[searchColumn]&"'>click here</a>"
You should be able to add your target _blank attribute using the above.
EDIT: A more comprehensive explanation of this technique...
Okay, so if you need to do something like add a target="_blank" attribute or dynamically generate a URL based on other data a list item contains, you need to use a calculated column.
You have some choices here, but you cannot use the 'Hyperlink or Picture' column type to define any of the data because it is not supported in calculated column field values.
In the most general case, you can use a text column to define the link value then use a calculated column as the column that you actually display in a list view.
Say you have a text field called 'linkVal' where you enter in the URL for each list item that you want. It should contain a valid URL that you specify, but otherwise it won't have any other restrictions.
What I'm proposing above, is that in a scenario like this, you can use a calculated column to display a link to this URL, that will also have the target attribute set so that the link opens in a new window.
Your calculated column would have a formula value like this:
="<a href='"&[linkVal]&"' target='_blank'>Click Here</a>"
This could also be expanded if you included another field on each list item that could have a value for the text inside the a tag. Let's say you had an additional field called 'linkDescrip' -- then you could use a calculated column formula like this:
="<a href='"&[linkVal]&"' target='_blank'>"&[linkDescrip]&"</a>"
And the link's href value will take the linkVal column's value, and the description shown for the link will be the value in the linkDescrip column.
Remember to ensure that your calculated column is returning a number by selecting 'Number' after the prompt at the bottom of the column settings page labeled 'The data type returned from this formula is'. This is important, as data that is returned as a number will be calculated by the SharePoint server.