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 | 2 |
| 3 | 3 |
| 4 | 7 |
| 5 | 12 |
| 6 | 36 |
| 7 | 89 |
| 8 | 322 |
| 9 | 1137 |
| 10 | 4704 |
| 11 | 19839 |
| 12 | 88508 |
| 13 | 399680 |
| 14 | 1839947 |
| 15 | 8533488 |
| 16 | 39893901 |
| 17 | 187393550 |
| 18 | 884153396 |
| 19 | 4185740195 |
| 20 | 19876594537 |
| 21 | 94633345608 |
| 22 | 451615319433 |
| 23 | 2159769331317 |
| 24 | 10348546548695 |
| 25 | 49672000435724 |
| 26 | 238804871206358 |
| 27 | 1149792978954373 |
| 28 | 5543621482141513 |