How to describe accession numbers on the academic paper?

In general, see the rule of the journal (i.e. Instructions to Authors), and follow it.

At INSDC, we recommend you to describe accession numbers in the footnote on the title page of your paper as following;
Note: Nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession number(s)—-‘.