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 | 19 |
| 2 | 140 |
| 3 | 660 |
| 4 | 2370 |
| 5 | 7062 |
| 6 | 18348 |
| 7 | 42900 |
| 8 | 92235 |
| 9 | 185185 |
| 10 | 351208 |
| 11 | 634712 |
| 12 | 1100580 |
| 13 | 1841100 |
| 14 | 2984520 |
| 15 | 4705464 |
| 16 | 7237461 |
| 17 | 10887855 |
| 18 | 16055380 |
| 19 | 23250700 |
| 20 | 33120230 |
| 21 | 46473570 |
| 22 | 64314900 |
| 23 | 87878700 |