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 | 1 |
| 2 | 6 |
| 3 | 21 |
| 4 | 60 |
| 5 | 155 |
| 6 | 378 |
| 7 | 889 |
| 8 | 2040 |
| 9 | 4599 |
| 10 | 10230 |
| 11 | 22517 |
| 12 | 49140 |
| 13 | 106483 |
| 14 | 229362 |
| 15 | 491505 |
| 16 | 1048560 |
| 17 | 2228207 |
| 18 | 4718574 |
| 19 | 9961453 |
| 20 | 20971500 |
| 21 | 44040171 |
| 22 | 92274666 |
| 23 | 192937961 |
| 24 | 402653160 |
| 25 | 838860775 |
| 26 | 1744830438 |
| 27 | 3623878629 |
| 28 | 7516192740 |
| 29 | 15569256419 |
| 30 | 32212254690 |