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 | 0 |
| 1 | 2 |
| 2 | 5 |
| 3 | 24 |
| 4 | 169 |
| 5 | 1572 |
| 6 | 18208 |
| 7 | 252676 |
| 8 | 4088138 |
| 9 | 75571648 |
| 10 | 1571427096 |
| 11 | 36304942704 |
| 12 | 922615912656 |
| 13 | 25577663099232 |
| 14 | 768176940800592 |
| 15 | 24845381066244288 |
| 16 | 860979848497650768 |
| 17 | 31825036424306681088 |
| 18 | 1249895536243141292544 |
| 19 | 51975908060575367916288 |