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 | 9 |
| 2 | 25 |
| 3 | 113 |
| 4 | 401 |
| 5 | 1593 |
| 6 | 5993 |
| 7 | 23137 |
| 8 | 88225 |
| 9 | 338409 |
| 10 | 1294393 |
| 11 | 4957649 |
| 12 | 18976049 |
| 13 | 72655641 |
| 14 | 278143625 |
| 15 | 1064876737 |
| 16 | 4076758849 |
| 17 | 15607654857 |
| 18 | 59752621657 |
| 19 | 228758827313 |
| 20 | 875786006225 |
| 21 | 3352883803641 |
| 22 | 12836269650857 |
| 23 | 49142725927201 |