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 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 16 |
| 5 | 74 |
| 6 | 364 |
| 7 | 1876 |
| 8 | 9993 |
| 9 | 54582 |
| 10 | 304040 |
| 11 | 1720576 |
| 12 | 9864114 |
| 13 | 57169168 |
| 14 | 334404892 |
| 15 | 1971641096 |
| 16 | 11705119157 |
| 17 | 69911438676 |
| 18 | 419798442416 |
| 19 | 2532791105844 |
| 20 | 15346498242460 |
| 21 | 93344296450020 |
| 22 | 569741502841020 |
| 23 | 3488539758461880 |
| 24 | 21422341792366320 |