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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 19 |
| 5 | 50 |
| 6 | 130 |
| 7 | 341 |
| 8 | 893 |
| 9 | 2337 |
| 10 | 6119 |
| 11 | 16020 |
| 12 | 41940 |
| 13 | 109801 |
| 14 | 287463 |
| 15 | 752587 |
| 16 | 1970299 |
| 17 | 5158310 |
| 18 | 13504630 |
| 19 | 35355581 |
| 20 | 92562113 |
| 21 | 242330757 |
| 22 | 634430159 |
| 23 | 1660959720 |
| 24 | 4348449000 |
| 25 | 11384387281 |
| 26 | 29804712843 |
| 27 | 78029751247 |
| 28 | 204284540899 |