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 | 1 |
| 2 | 1 |
| 3 | 7 |
| 4 | 37 |
| 5 | 151 |
| 6 | 541 |
| 7 | 1807 |
| 8 | 5797 |
| 9 | 18151 |
| 10 | 55981 |
| 11 | 171007 |
| 12 | 519157 |
| 13 | 1569751 |
| 14 | 4733821 |
| 15 | 14250607 |
| 16 | 42850117 |
| 17 | 128746951 |
| 18 | 386634061 |
| 19 | 1160688607 |
| 20 | 3483638677 |
| 21 | 10454061751 |
| 22 | 31368476701 |
| 23 | 94118013007 |
| 24 | 282379204837 |
| 25 | 847187946151 |
| 26 | 2541664501741 |
| 27 | 7625194831807 |