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 | 3 |
| 2 | 21 |
| 3 | 192 |
| 4 | 2154 |
| 5 | 28434 |
| 6 | 429213 |
| 7 | 7261788 |
| 8 | 135698268 |
| 9 | 2769463335 |
| 10 | 61186736415 |
| 11 | 1452889463034 |
| 12 | 36857766745749 |
| 13 | 993941679586098 |
| 14 | 28370018078000985 |
| 15 | 853903169641805925 |
| 16 | 27014392815958815969 |
| 17 | 895723118730738795837 |
| 18 | 31048284069527339602902 |