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 | 1 |
| 2 | 3 |
| 3 | 14 |
| 4 | 85 |
| 5 | 671 |
| 6 | 6405 |
| 7 | 72302 |
| 8 | 940005 |
| 9 | 13846117 |
| 10 | 227837533 |
| 11 | 4142793511 |
| 12 | 82488063476 |
| 13 | 1785049505682 |
| 14 | 41715243815059 |
| 15 | 1046997553798894 |
| 16 | 28089178205661221 |
| 17 | 802173732190546289 |
| 18 | 24296253228394108980 |
| 19 | 777918130180655893150 |
| 20 | 26253270588637259772768 |