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 | 7 |
| 3 | 45 |
| 4 | 286 |
| 5 | 1820 |
| 6 | 11628 |
| 7 | 74613 |
| 8 | 480700 |
| 9 | 3108105 |
| 10 | 20160075 |
| 11 | 131128140 |
| 12 | 854992152 |
| 13 | 5586853480 |
| 14 | 36576848168 |
| 15 | 239877544005 |
| 16 | 1575580702584 |
| 17 | 10363194502115 |
| 18 | 68248282427325 |
| 19 | 449972009097765 |
| 20 | 2969831763694950 |
| 21 | 19619725782651120 |
| 22 | 129728497393775280 |