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 | 7 |
| 3 | 30 |
| 4 | 143 |
| 5 | 728 |
| 6 | 3876 |
| 7 | 21318 |
| 8 | 120175 |
| 9 | 690690 |
| 10 | 4032015 |
| 11 | 23841480 |
| 12 | 142498692 |
| 13 | 859515920 |
| 14 | 5225264024 |
| 15 | 31983672534 |
| 16 | 196947587823 |
| 17 | 1219199353190 |
| 18 | 7583142491925 |
| 19 | 47365474641870 |
| 20 | 296983176369495 |
| 21 | 1868545312633440 |
| 22 | 11793499763070480 |