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 | 6 |
| 3 | 24 |
| 4 | 99 |
| 5 | 397 |
| 6 | 1590 |
| 7 | 6360 |
| 8 | 25443 |
| 9 | 101773 |
| 10 | 407094 |
| 11 | 1628376 |
| 12 | 6513507 |
| 13 | 26054029 |
| 14 | 104216118 |
| 15 | 416864472 |
| 16 | 1667457891 |
| 17 | 6669831565 |
| 18 | 26679326262 |
| 19 | 106717305048 |
| 20 | 426869220195 |
| 21 | 1707476880781 |
| 22 | 6829907523126 |
| 23 | 27319630092504 |