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 | 144 |
| 5 | 541 |
| 6 | 3258 |
| 7 | 12275 |
| 8 | 74280 |
| 9 | 282003 |
| 10 | 1713690 |
| 11 | 6549906 |
| 12 | 39938616 |
| 13 | 153481299 |
| 14 | 938430990 |
| 15 | 3622111560 |
| 16 | 22195961280 |
| 17 | 85975792075 |
| 18 | 527816696850 |
| 19 | 2050493623760 |
| 20 | 12607504827600 |
| 21 | 49098707209695 |
| 22 | 302275142049870 |
| 23 | 1179633190545755 |
| 24 | 7270432009471224 |
| 25 | 28423658754983701 |