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 | 5 |
| 3 | 26 |
| 4 | 134 |
| 5 | 670 |
| 6 | 3262 |
| 7 | 15540 |
| 8 | 72732 |
| 9 | 335478 |
| 10 | 1528670 |
| 11 | 6894316 |
| 12 | 30820660 |
| 13 | 136736236 |
| 14 | 602610764 |
| 15 | 2640266600 |
| 16 | 11508115320 |
| 17 | 49928451750 |
| 18 | 215717144670 |
| 19 | 928515985980 |
| 20 | 3983029119300 |
| 21 | 17032882625220 |
| 22 | 72631992447300 |
| 23 | 308911087394520 |
| 24 | 1310670689270280 |
| 25 | 5548646191175100 |