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) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 25 |
| 4 | 213 |
| 5 | 2131 |
| 6 | 23729 |
| 7 | 283681 |
| 8 | 3574222 |
| 9 | 46866712 |
| 10 | 634204317 |
| 11 | 8803501719 |
| 12 | 124799484286 |
| 13 | 1800669899917 |
| 14 | 26374204955323 |
| 15 | 391331674556361 |
| 16 | 5872226011836383 |
| 17 | 88993282402441857 |
| 18 | 1360552594176453319 |