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 | 5 |
| 2 | 35 |
| 3 | 105 |
| 4 | 1155 |
| 5 | 3003 |
| 6 | 15015 |
| 7 | 36465 |
| 8 | 692835 |
| 9 | 1616615 |
| 10 | 7436429 |
| 11 | 16900975 |
| 12 | 152108775 |
| 13 | 339319575 |
| 14 | 1502700975 |
| 15 | 3305942145 |
| 16 | 115707975075 |
| 17 | 251835004575 |
| 18 | 1091285019825 |
| 19 | 2354878200675 |
| 20 | 20251952525805 |
| 21 | 43397041126725 |
| 22 | 185423721177825 |
| 23 | 395033145117975 |