This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 25 |
| 4 | 208 |
| 5 | 2161 |
| 6 | 26944 |
| 7 | 391945 |
| 8 | 6515968 |
| 9 | 121866721 |
| 10 | 2532496384 |
| 11 | 57890223865 |
| 12 | 1443611004928 |
| 13 | 38999338931281 |
| 14 | 1134616226381824 |
| 15 | 35367467110007785 |
| 16 | 1175946733416153088 |
| 17 | 41543231955279099841 |
| 18 | 1553948045857778827264 |
| 19 | 61355543097139813855705 |