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 | 2 |
| 2 | 6 |
| 3 | 20 |
| 4 | 71 |
| 5 | 256 |
| 6 | 938 |
| 7 | 3480 |
| 8 | 13041 |
| 9 | 49234 |
| 10 | 186968 |
| 11 | 713428 |
| 12 | 2733218 |
| 13 | 10506788 |
| 14 | 40506442 |
| 15 | 156554820 |
| 16 | 606400307 |
| 17 | 2353368138 |
| 18 | 9148789134 |
| 19 | 35620615548 |
| 20 | 138878821241 |
| 21 | 542138013480 |
| 22 | 2118718654794 |
| 23 | 8288638523100 |
| 24 | 32456517032946 |