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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 35 |
| 5 | 136 |
| 6 | 577 |
| 7 | 2682 |
| 8 | 13435 |
| 9 | 72310 |
| 10 | 414761 |
| 11 | 2524666 |
| 12 | 16239115 |
| 13 | 109976478 |
| 14 | 781672543 |
| 15 | 5814797281 |
| 16 | 45155050875 |
| 17 | 365223239372 |
| 18 | 3070422740989 |
| 19 | 26780417126048 |
| 20 | 241927307839731 |
| 21 | 2260138776632752 |
| 22 | 21805163768404127 |
| 23 | 216970086170175575 |
| 24 | 2224040977932468379 |