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 | 2 |
| 2 | 10 |
| 3 | 84 |
| 4 | 1028 |
| 5 | 15630 |
| 6 | 279942 |
| 7 | 5764808 |
| 8 | 134217736 |
| 9 | 3486784410 |
| 10 | 100000000010 |
| 11 | 3138428376732 |
| 12 | 106993205379084 |
| 13 | 3937376385699302 |
| 14 | 155568095557812238 |
| 15 | 6568408355712890640 |
| 16 | 295147905179352825872 |
| 17 | 14063084452067724991026 |
| 18 | 708235345355337676357650 |
| 19 | 37589973457545958193355620 |