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) |
|---|---|
| 1 | 6 |
| 2 | 63 |
| 3 | 486 |
| 4 | 3351 |
| 5 | 20040 |
| 6 | 107015 |
| 7 | 516084 |
| 8 | 2278687 |
| 9 | 9303052 |
| 10 | 35428544 |
| 11 | 126753732 |
| 12 | 428651446 |
| 13 | 1377310514 |
| 14 | 4223642819 |
| 15 | 12409437728 |
| 16 | 35050866249 |
| 17 | 95459908872 |
| 18 | 251341796912 |
| 19 | 641282264972 |
| 20 | 1588863292072 |