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 | 1 |
| 2 | 6 |
| 3 | 18 |
| 4 | 70 |
| 5 | 246 |
| 6 | 924 |
| 7 | 3412 |
| 8 | 12870 |
| 9 | 48550 |
| 10 | 184756 |
| 11 | 705180 |
| 12 | 2704156 |
| 13 | 10399676 |
| 14 | 40116600 |
| 15 | 155114088 |
| 16 | 601080390 |
| 17 | 2333593350 |
| 18 | 9075135300 |
| 19 | 35345215180 |
| 20 | 137846528820 |
| 21 | 538257689684 |
| 22 | 2104098963720 |
| 23 | 8233430022168 |
| 24 | 32247603683100 |