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 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 18 |
| 6 | 64 |
| 7 | 226 |
| 8 | 856 |
| 9 | 3306 |
| 10 | 13249 |
| 11 | 53794 |
| 12 | 222717 |
| 13 | 933438 |
| 14 | 3960487 |
| 15 | 16970362 |
| 16 | 73381453 |
| 17 | 319817670 |
| 18 | 1403875491 |
| 19 | 6202064928 |
| 20 | 27559699507 |
| 21 | 123115236582 |
| 22 | 552654175124 |
| 23 | 2491870281372 |
| 24 | 11281732737898 |
| 25 | 51270697159708 |
| 26 | 233822055167579 |
| 27 | 1069835253304014 |
| 28 | 4909835353596645 |
| 29 | 22596879316320522 |