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 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 14 |
| 5 | 77 |
| 6 | 497 |
| 7 | 3676 |
| 8 | 30677 |
| 9 | 285335 |
| 10 | 2928846 |
| 11 | 32903721 |
| 12 | 401739797 |
| 13 | 5298600772 |
| 14 | 75092880273 |
| 15 | 1138261010851 |
| 16 | 18378421938366 |
| 17 | 314928827507717 |
| 18 | 5708689036074089 |
| 19 | 109145365739197964 |
| 20 | 2195167574579322013 |
| 21 | 46331767712354136479 |
| 22 | 1023970009016490622478 |