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 | 3 |
| 2 | 10 |
| 3 | 76 |
| 4 | 264 |
| 5 | 2208 |
| 6 | 7744 |
| 7 | 67776 |
| 8 | 238720 |
| 9 | 2144768 |
| 10 | 7572480 |
| 11 | 69203968 |
| 12 | 244715520 |
| 13 | 2263351296 |
| 14 | 8012201984 |
| 15 | 74764042240 |
| 16 | 264873738240 |
| 17 | 2488551997440 |
| 18 | 8821831106560 |
| 19 | 83334108020736 |
| 20 | 295559851147264 |
| 21 | 2804309838266368 |