I already found the human chromosome DNA sequence from the ensemble browser .But the problem is in that sequence it shows some N terms are coming top , bottom and in the middle .Without N terms how can I get the data .?
prefer to use NCBI tools and data to download (https://www.ncbi.nlm.nih.gov/genome/guide/human/#download) for this kind of request. You'll just need to choose the right genome build and fix it for further analysis.