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 | 13 |
| 3 | 99 |
| 4 | 605 |
| 5 | 3289 |
| 6 | 16653 |
| 7 | 80444 |
| 8 | 375972 |
| 9 | 1715130 |
| 10 | 7681586 |
| 11 | 33913385 |
| 12 | 148018455 |
| 13 | 640049865 |
| 14 | 2746422525 |
| 15 | 11708971560 |
| 16 | 49647131160 |
| 17 | 209523969630 |
| 18 | 880668859590 |
| 19 | 3688555690950 |
| 20 | 15401089588794 |
| 21 | 64128925255626 |
| 22 | 266376231244178 |
| 23 | 1104047701891624 |
| 24 | 4566956385797400 |