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 | 15 |
| 1 | 210 |
| 2 | 1750 |
| 3 | 11368 |
| 4 | 63805 |
| 5 | 325930 |
| 6 | 1561516 |
| 7 | 7150000 |
| 8 | 31682651 |
| 9 | 137031986 |
| 10 | 582035714 |
| 11 | 2438479592 |
| 12 | 10109790809 |
| 13 | 41579014154 |
| 14 | 169946747160 |
| 15 | 691299506640 |
| 16 | 2801567046135 |
| 17 | 11320801495410 |
| 18 | 45642930545070 |
| 19 | 183698923750440 |