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 | 6 |
| 2 | 30 |
| 3 | 136 |
| 4 | 579 |
| 5 | 2358 |
| 6 | 9288 |
| 7 | 35640 |
| 8 | 133893 |
| 9 | 494262 |
| 10 | 1797714 |
| 11 | 6456024 |
| 12 | 22930695 |
| 13 | 80660934 |
| 14 | 281309436 |
| 15 | 973599912 |
| 16 | 3346483977 |
| 17 | 11431295910 |
| 18 | 38828142342 |
| 19 | 131206405608 |
| 20 | 441271936971 |
| 21 | 1477621745046 |
| 22 | 4927988620080 |
| 23 | 16373939547096 |