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 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 17 |
| 5 | 41 |
| 6 | 100 |
| 7 | 240 |
| 8 | 580 |
| 9 | 1400 |
| 10 | 3380 |
| 11 | 8160 |
| 12 | 19700 |
| 13 | 47560 |
| 14 | 114820 |
| 15 | 277200 |
| 16 | 669220 |
| 17 | 1615640 |
| 18 | 3900500 |
| 19 | 9416640 |
| 20 | 22733780 |
| 21 | 54884200 |
| 22 | 132502180 |
| 23 | 319888560 |
| 24 | 772279300 |
| 25 | 1864447160 |
| 26 | 4501173620 |
| 27 | 10866794400 |
| 28 | 26234762420 |
| 29 | 63336319240 |