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 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 22 |
| 5 | 139 |
| 6 | 979 |
| 7 | 7484 |
| 8 | 61018 |
| 9 | 523995 |
| 10 | 4696277 |
| 11 | 43623618 |
| 12 | 417729564 |
| 13 | 4106089683 |
| 14 | 41289287337 |
| 15 | 423556384020 |
| 16 | 4422308778458 |
| 17 | 46904447607369 |
| 18 | 504544306691569 |
| 19 | 5496706186024364 |
| 20 | 60576765646658782 |
| 21 | 674624324569952719 |
| 22 | 7585425185883023881 |