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 | 1 |
| 3 | 3 |
| 4 | 12 |
| 5 | 56 |
| 6 | 289 |
| 7 | 1602 |
| 8 | 9367 |
| 9 | 57075 |
| 10 | 359346 |
| 11 | 2323416 |
| 12 | 15356446 |
| 13 | 103389175 |
| 14 | 707107627 |
| 15 | 4901988047 |
| 16 | 34384943850 |
| 17 | 243694702311 |
| 18 | 1742953208739 |
| 19 | 12567593026554 |
| 20 | 91280392585747 |
| 21 | 667341975412356 |
| 22 | 4907899368783645 |
| 23 | 36289929612761691 |
| 24 | 269660272111724536 |
| 25 | 2012845416966620068 |
| 26 | 15087243969226496324 |
| 27 | 113521159338891300347 |
| 28 | 857211201390859034536 |