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 | 17 |
| 4 | 83 |
| 5 | 394 |
| 6 | 2278 |
| 7 | 13949 |
| 8 | 93898 |
| 9 | 670003 |
| 10 | 5059914 |
| 11 | 40033149 |
| 12 | 330555726 |
| 13 | 2836763749 |
| 14 | 25233047351 |
| 15 | 232080785282 |
| 16 | 2202802051834 |
| 17 | 21539083861802 |
| 18 | 216638327167235 |
| 19 | 2238260395921444 |
| 20 | 23725940481578999 |