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 | 4 |
| 2 | 14 |
| 3 | 52 |
| 4 | 217 |
| 5 | 1040 |
| 6 | 5768 |
| 7 | 36992 |
| 8 | 272584 |
| 9 | 2285184 |
| 10 | 21550656 |
| 11 | 226071744 |
| 12 | 2611146384 |
| 13 | 32911082496 |
| 14 | 449243785728 |
| 15 | 6598780563456 |
| 16 | 103734755882496 |
| 17 | 1737181702840320 |
| 18 | 30866291090657280 |
| 19 | 579859321408266240 |