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 | 2 |
| 2 | 11 |
| 3 | 54 |
| 4 | 279 |
| 5 | 1442 |
| 6 | 7530 |
| 7 | 39474 |
| 8 | 207693 |
| 9 | 1095522 |
| 10 | 5790116 |
| 11 | 30650038 |
| 12 | 162451560 |
| 13 | 861920492 |
| 14 | 4577055823 |
| 15 | 24323292984 |
| 16 | 129338944225 |
| 17 | 688128700422 |
| 18 | 3662798123481 |
| 19 | 19504467792378 |
| 20 | 103899170100154 |
| 21 | 553642311668244 |
| 22 | 2951010332435759 |
| 23 | 15733439067954134 |