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 | 14 |
| 3 | 138 |
| 4 | 1522 |
| 5 | 17740 |
| 6 | 213642 |
| 7 | 2628626 |
| 8 | 32833226 |
| 9 | 414697740 |
| 10 | 5282720764 |
| 11 | 67750624480 |
| 12 | 873653602902 |
| 13 | 11316723314858 |
| 14 | 147143725788662 |
| 15 | 1919360958676866 |
| 16 | 25105597581410410 |
| 17 | 329174706398378884 |
| 18 | 4325098764217263996 |
| 19 | 56934186664360843064 |