According to [link|https://partsurfer.hp.com/partsurfer/?searchtext=183H1PA&searchby=product|HP’s part’s catalog|new_window=true], the part number you need is L98738-001. You can likely find any number of vendors for these. Sometimes you can buy parts from HP Partsurfer, even as a consumer, but it does not appear that this fan is one of them. But I found listings in a few other places with just some quick web searching.