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 | 2 |
| 1 | 11 |
| 2 | 54 |
| 3 | 252 |
| 4 | 1134 |
| 5 | 4977 |
| 6 | 21438 |
| 7 | 91017 |
| 8 | 381996 |
| 9 | 1588248 |
| 10 | 6552252 |
| 11 | 26853687 |
| 12 | 109438938 |
| 13 | 443837799 |
| 14 | 1792373346 |
| 15 | 7211142612 |
| 16 | 28915704810 |
| 17 | 115603540605 |
| 18 | 460942202070 |
| 19 | 1833459620517 |
| 20 | 7276826042712 |
| 21 | 28823185892016 |
| 22 | 113957884236024 |
| 23 | 449793742386627 |