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 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 20 |
| 5 | 53 |
| 6 | 136 |
| 7 | 383 |
| 8 | 1067 |
| 9 | 3292 |
| 10 | 10162 |
| 11 | 34586 |
| 12 | 118332 |
| 13 | 441898 |
| 14 | 1660947 |
| 15 | 6745710 |
| 16 | 27575425 |
| 17 | 120801230 |
| 18 | 532530170 |
| 19 | 2499230441 |
| 20 | 11800052796 |
| 21 | 58992236094 |
| 22 | 296630364605 |
| 23 | 1572128197439 |
| 24 | 8378539879636 |
| 25 | 46882666240016 |
| 26 | 263735138346443 |
| 27 | 1552510947814406 |