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 | 5 |
| 3 | 26 |
| 4 | 145 |
| 5 | 841 |
| 6 | 5006 |
| 7 | 30350 |
| 8 | 186537 |
| 9 | 1158685 |
| 10 | 7258145 |
| 11 | 45779420 |
| 12 | 290399030 |
| 13 | 1851032314 |
| 14 | 11847434810 |
| 15 | 76100034106 |
| 16 | 490343021881 |
| 17 | 3168174174105 |
| 18 | 20520045125681 |
| 19 | 133197288251330 |
| 20 | 866293102078525 |
| 21 | 5644234561103785 |