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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 8 |
| 5 | 36 |
| 6 | 120 |
| 7 | 331 |
| 8 | 808 |
| 9 | 1852 |
| 10 | 4248 |
| 11 | 10312 |
| 12 | 26968 |
| 13 | 74012 |
| 14 | 204968 |
| 15 | 558253 |
| 16 | 1483336 |
| 17 | 3860588 |
| 18 | 9938488 |
| 19 | 25570103 |
| 20 | 66214096 |
| 21 | 172926104 |
| 22 | 454504816 |
| 23 | 1197527184 |
| 24 | 3152221296 |
| 25 | 8275051544 |
| 26 | 21663395536 |
| 27 | 56615219385 |
| 28 | 147898879304 |
| 29 | 386593228980 |
| 30 | 1011521607736 |