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 | 21 |
| 4 | 60 |
| 5 | 216 |
| 6 | 540 |
| 7 | 1836 |
| 8 | 4320 |
| 9 | 14256 |
| 10 | 32400 |
| 11 | 104976 |
| 12 | 233280 |
| 13 | 746496 |
| 14 | 1632960 |
| 15 | 5178816 |
| 16 | 11197440 |
| 17 | 35271936 |
| 18 | 75582720 |
| 19 | 236825856 |
| 20 | 503884800 |
| 21 | 1572120576 |
| 22 | 3325639680 |
| 23 | 10339716096 |
| 24 | 21767823360 |
| 25 | 67480252416 |
| 26 | 141490851840 |