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 | 3 |
| 3 | 9 |
| 4 | 25 |
| 5 | 87 |
| 6 | 307 |
| 7 | 1113 |
| 8 | 4149 |
| 9 | 15605 |
| 10 | 59201 |
| 11 | 225999 |
| 12 | 866449 |
| 13 | 3333847 |
| 14 | 12865335 |
| 15 | 49769689 |
| 16 | 192945411 |
| 17 | 749396493 |
| 18 | 2915432049 |
| 19 | 11358771965 |
| 20 | 44313108627 |
| 21 | 173081422997 |
| 22 | 676766482917 |
| 23 | 2648843996031 |
| 24 | 10376891445525 |
| 25 | 40685535827325 |
| 26 | 159641884780749 |
| 27 | 626849029013919 |
| 28 | 2463010645910537 |
| 29 | 9683604464279235 |