n# + 1
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
53: | \[241\#+1\] | 3499 × 23154953 × 14209707448699806612680132420076872871953<41> × 222401033703390757472499600738273084231948675841<48> |