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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 7 |
| 4 | 37 |
| 5 | 183 |
| 6 | 893 |
| 7 | 4351 |
| 8 | 21205 |
| 9 | 103367 |
| 10 | 503917 |
| 11 | 2456655 |
| 12 | 11976517 |
| 13 | 58387095 |
| 14 | 284644701 |
| 15 | 1387679903 |
| 16 | 6765119669 |
| 17 | 32980836455 |
| 18 | 160785858381 |
| 19 | 783851928559 |
| 20 | 3821379890981 |
| 21 | 18629722961207 |
| 22 | 90822317465149 |
| 23 | 442770585849407 |