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 | 3 |
| 2 | 26 |
| 3 | 305 |
| 4 | 4120 |
| 5 | 60398 |
| 6 | 934064 |
| 7 | 15000903 |
| 8 | 247766620 |
| 9 | 4182015080 |
| 10 | 71816825856 |
| 11 | 1250772245698 |
| 12 | 22039796891026 |
| 13 | 392213323252200 |
| 14 | 7038863826811100 |
| 15 | 127248841020380105 |
| 16 | 2315130641074743540 |
| 17 | 42358284517663463380 |
| 18 | 778876539384226875800 |