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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 2 |
| 7 | 5 |
| 8 | 13 |
| 9 | 34 |
| 10 | 90 |
| 11 | 247 |
| 12 | 720 |
| 13 | 2256 |
| 14 | 7568 |
| 15 | 26814 |
| 16 | 98982 |
| 17 | 377541 |
| 18 | 1484254 |
| 19 | 6021789 |
| 20 | 25271173 |
| 21 | 109850447 |
| 22 | 494355359 |
| 23 | 2298362532 |
| 24 | 11008133629 |
| 25 | 54175202125 |
| 26 | 273460921605 |
| 27 | 1414449612648 |
| 28 | 7494262602464 |
| 29 | 40669492399396 |