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 | 0 |
| 2 | 0 |
| 3 | 4 |
| 4 | 16 |
| 5 | 53 |
| 6 | 172 |
| 7 | 568 |
| 8 | 1906 |
| 9 | 6471 |
| 10 | 22200 |
| 11 | 76884 |
| 12 | 268350 |
| 13 | 942649 |
| 14 | 3329606 |
| 15 | 11817580 |
| 16 | 42120338 |
| 17 | 150682448 |
| 18 | 540832272 |
| 19 | 1946892840 |
| 20 | 7027047846 |
| 21 | 25424079337 |
| 22 | 92185846606 |
| 23 | 334925007126 |
| 24 | 1219054432488 |
| 25 | 4444545298877 |
| 26 | 16229462702150 |
| 27 | 59347661054362 |