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 | 2 |
| 2 | 6 |
| 3 | 21 |
| 4 | 82 |
| 5 | 356 |
| 6 | 1690 |
| 7 | 8731 |
| 8 | 48213 |
| 9 | 281885 |
| 10 | 1724817 |
| 11 | 10955956 |
| 12 | 71747613 |
| 13 | 481927039 |
| 14 | 3306721747 |
| 15 | 23103546417 |
| 16 | 163954719933 |
| 17 | 1179368199427 |
| 18 | 8584854507319 |
| 19 | 63150696347462 |
| 20 | 468906907743356 |
| 21 | 3511055861792836 |
| 22 | 26489459993078577 |
| 23 | 201226384388401603 |