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 | 18 |
| 2 | 126 |
| 3 | 570 |
| 4 | 1980 |
| 5 | 5742 |
| 6 | 14586 |
| 7 | 33462 |
| 8 | 70785 |
| 9 | 140140 |
| 10 | 262548 |
| 11 | 469404 |
| 12 | 806208 |
| 13 | 1337220 |
| 14 | 2151180 |
| 15 | 3368244 |
| 16 | 5148297 |
| 17 | 7700814 |
| 18 | 11296450 |
| 19 | 16280550 |
| 20 | 23088780 |
| 21 | 32265090 |
| 22 | 44482230 |
| 23 | 60565050 |
| 24 | 81516825 |
| 25 | 108548856 |
| 26 | 143113608 |
| 27 | 186941656 |