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 | 4 |
| 2 | 12 |
| 3 | 44 |
| 4 | 172 |
| 5 | 772 |
| 6 | 3308 |
| 7 | 14924 |
| 8 | 64956 |
| 9 | 294252 |
| 10 | 1301044 |
| 11 | 5930588 |
| 12 | 26506948 |
| 13 | 121290940 |
| 14 | 546050988 |
| 15 | 2505533940 |
| 16 | 11340303508 |
| 17 | 52147596788 |
| 18 | 236995050900 |
| 19 | 1091701675948 |
| 20 | 4977541017540 |
| 21 | 22961416861940 |
| 22 | 104965762062612 |