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 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 8 |
| 7 | 18 |
| 8 | 47 |
| 9 | 137 |
| 10 | 464 |
| 11 | 1793 |
| 12 | 8167 |
| 13 | 43645 |
| 14 | 275480 |
| 15 | 2045279 |
| 16 | 17772647 |
| 17 | 179593823 |
| 18 | 2098423758 |
| 19 | 28215583324 |
| 20 | 434936005284 |
| 21 | 7662164738118 |