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 | 1 |
| 4 | 3 |
| 5 | 8 |
| 6 | 24 |
| 7 | 70 |
| 8 | 224 |
| 9 | 744 |
| 10 | 2588 |
| 11 | 9317 |
| 12 | 34924 |
| 13 | 135297 |
| 14 | 542123 |
| 15 | 2236834 |
| 16 | 9508297 |
| 17 | 41511215 |
| 18 | 186109781 |
| 19 | 854874944 |
| 20 | 4021672983 |
| 21 | 19344343843 |
| 22 | 95093249014 |
| 23 | 477137036748 |
| 24 | 2442413708120 |
| 25 | 12742038926613 |
| 26 | 67714763161526 |
| 27 | 366266085720565 |
| 28 | 2015454903261855 |