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 | 15 |
| 4 | 80 |
| 5 | 466 |
| 6 | 2863 |
| 7 | 18265 |
| 8 | 119856 |
| 9 | 803815 |
| 10 | 5485100 |
| 11 | 37962429 |
| 12 | 265843161 |
| 13 | 1880196279 |
| 14 | 13411084410 |
| 15 | 96363049074 |
| 16 | 696851538230 |
| 17 | 5067830579847 |
| 18 | 37040831752291 |
| 19 | 271947326550486 |
| 20 | 2004646999165517 |
| 21 | 14831053502690715 |
| 22 | 110088540151473330 |
| 23 | 819638482252323929 |
| 24 | 6119312652926134529 |