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 | 4 |
| 3 | 9 |
| 4 | 21 |
| 5 | 49 |
| 6 | 114 |
| 7 | 266 |
| 8 | 620 |
| 9 | 1446 |
| 10 | 3372 |
| 11 | 7864 |
| 12 | 18340 |
| 13 | 42772 |
| 14 | 99752 |
| 15 | 232640 |
| 16 | 542560 |
| 17 | 1265352 |
| 18 | 2951040 |
| 19 | 6882384 |
| 20 | 16051024 |
| 21 | 37434032 |
| 22 | 87303264 |
| 23 | 203607776 |
| 24 | 474851968 |
| 25 | 1107444896 |
| 26 | 2582771648 |
| 27 | 6023513600 |
| 28 | 14047976768 |
| 29 | 32762547648 |
| 30 | 76408478336 |