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 | 8 |
| 3 | 50 |
| 4 | 392 |
| 5 | 3602 |
| 6 | 37928 |
| 7 | 451250 |
| 8 | 5995592 |
| 9 | 88073042 |
| 10 | 1418137448 |
| 11 | 24846302450 |
| 12 | 470675213192 |
| 13 | 9587626273682 |
| 14 | 209000505036968 |
| 15 | 4855088300025650 |
| 16 | 119739457665173192 |
| 17 | 3124793129198573522 |
| 18 | 86030517992814720488 |
| 19 | 2492084621605727380850 |
| 20 | 75769449406015305475592 |