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 | 4 |
| 2 | 12 |
| 3 | 60 |
| 4 | 400 |
| 5 | 2960 |
| 6 | 24600 |
| 7 | 221072 |
| 8 | 2076744 |
| 9 | 20123080 |
| 10 | 197757768 |
| 11 | 1937125160 |
| 12 | 18687793880 |
| 13 | 175793675328 |
| 14 | 1594744777464 |
| 15 | 13794351556920 |
| 16 | 112576101214496 |
| 17 | 857945953884624 |
| 18 | 6037935953538456 |
| 19 | 38729529837059648 |
| 20 | 222984258240522544 |
| 21 | 1133096911619304064 |
| 22 | 4985812137371331624 |