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 | 5 |
| 3 | 16 |
| 4 | 59 |
| 5 | 243 |
| 6 | 1101 |
| 7 | 5461 |
| 8 | 29619 |
| 9 | 175641 |
| 10 | 1137741 |
| 11 | 8031838 |
| 12 | 61569345 |
| 13 | 510230087 |
| 14 | 4549650423 |
| 15 | 43452408496 |
| 16 | 442620720531 |
| 17 | 4790322653809 |
| 18 | 54893121512453 |
| 19 | 663974736739232 |
| 20 | 8453986695437957 |
| 21 | 113021461431438475 |