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) |
|---|---|
| 9 | 1 |
| 10 | 9 |
| 11 | 45 |
| 12 | 165 |
| 13 | 495 |
| 14 | 1287 |
| 15 | 3003 |
| 16 | 6435 |
| 17 | 12870 |
| 18 | 24309 |
| 19 | 43758 |
| 20 | 75573 |
| 21 | 125970 |
| 22 | 203445 |
| 23 | 319770 |
| 24 | 490149 |
| 25 | 735471 |
| 26 | 1081080 |
| 27 | 1562274 |
| 28 | 2218788 |
| 29 | 3108105 |
| 30 | 4289133 |
| 31 | 5852925 |
| 32 | 7882290 |
| 33 | 10518255 |
| 34 | 13871286 |
| 35 | 18156204 |
| 36 | 23511345 |
| 37 | 30260340 |
| 38 | 38564262 |
| 39 | 48902997 |