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 | 0 |
| 2 | 1 |
| 3 | 10 |
| 4 | 73 |
| 5 | 490 |
| 6 | 3246 |
| 7 | 21814 |
| 8 | 150535 |
| 9 | 1072786 |
| 10 | 7915081 |
| 11 | 60512348 |
| 12 | 479371384 |
| 13 | 3932969516 |
| 14 | 33392961185 |
| 15 | 293143783762 |
| 16 | 2658128519225 |
| 17 | 24872012040510 |
| 18 | 239916007100054 |
| 19 | 2383444110867378 |
| 20 | 24363881751014383 |
| 21 | 256034413642582418 |
| 22 | 2763708806499744097 |