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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 5 |
| 4 | 18 |
| 5 | 58 |
| 6 | 177 |
| 7 | 522 |
| 8 | 1503 |
| 9 | 4252 |
| 10 | 11869 |
| 11 | 32787 |
| 12 | 89821 |
| 13 | 244415 |
| 14 | 661415 |
| 15 | 1781654 |
| 16 | 4780776 |
| 17 | 12786704 |
| 18 | 34104792 |
| 19 | 90749209 |
| 20 | 240982564 |
| 21 | 638800052 |
| 22 | 1690764378 |
| 23 | 4469170031 |
| 24 | 11799684559 |
| 25 | 31122693066 |
| 26 | 82016622160 |
| 27 | 215969175981 |
| 28 | 568313267862 |
| 29 | 1494601936229 |