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 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 22 |
| 5 | 129 |
| 6 | 1411 |
| 7 | 16813 |
| 8 | 266372 |
| 9 | 4787349 |
| 10 | 100391653 |
| 11 | 2357947701 |
| 12 | 61980047702 |
| 13 | 1792160394049 |
| 14 | 56707753687079 |
| 15 | 1946197516142925 |
| 16 | 72061992621375496 |
| 17 | 2862423051509815809 |
| 18 | 121441389759089405193 |
| 19 | 5480386857784802185957 |