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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 14 |
| 4 | 54 |
| 5 | 239 |
| 6 | 1007 |
| 7 | 4375 |
| 8 | 18728 |
| 9 | 80572 |
| 10 | 344651 |
| 11 | 1473402 |
| 12 | 6280556 |
| 13 | 26732173 |
| 14 | 113570050 |
| 15 | 481832209 |
| 16 | 2041461824 |
| 17 | 8639576140 |
| 18 | 36524803606 |
| 19 | 154269617690 |
| 20 | 651036955831 |
| 21 | 2745359144355 |