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 | 4 |
| 2 | 25 |
| 3 | 172 |
| 4 | 1201 |
| 5 | 8404 |
| 6 | 58825 |
| 7 | 411772 |
| 8 | 2882401 |
| 9 | 20176804 |
| 10 | 141237625 |
| 11 | 988663372 |
| 12 | 6920643601 |
| 13 | 48444505204 |
| 14 | 339111536425 |
| 15 | 2373780754972 |
| 16 | 16616465284801 |
| 17 | 116315256993604 |
| 18 | 814206798955225 |
| 19 | 5699447592686572 |
| 20 | 39896133148806001 |
| 21 | 279272932041642004 |