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 | 2 |
| 3 | 8 |
| 4 | 29 |
| 5 | 140 |
| 6 | 661 |
| 7 | 3622 |
| 8 | 19993 |
| 9 | 120909 |
| 10 | 744890 |
| 11 | 4887401 |
| 12 | 32795272 |
| 13 | 230728608 |
| 14 | 1661537689 |
| 15 | 12426619200 |
| 16 | 95087157771 |
| 17 | 750968991327 |
| 18 | 6062088334528 |
| 19 | 50288003979444 |
| 20 | 425889463252945 |
| 21 | 3694698371069796 |
| 22 | 32683415513480237 |
| 23 | 295430131502604353 |
| 24 | 2719833636188015674 |
| 25 | 25536232370225996575 |