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 | 4 |
| 1 | 14 |
| 2 | 49 |
| 3 | 171 |
| 4 | 596 |
| 5 | 2077 |
| 6 | 7238 |
| 7 | 25223 |
| 8 | 87897 |
| 9 | 306303 |
| 10 | 1067403 |
| 11 | 3719680 |
| 12 | 12962320 |
| 13 | 45171020 |
| 14 | 157411717 |
| 15 | 548547468 |
| 16 | 1911575138 |
| 17 | 6661446313 |
| 18 | 23213770727 |
| 19 | 80895217952 |
| 20 | 281903201529 |
| 21 | 982374694626 |
| 22 | 3423373822671 |
| 23 | 11929753885009 |
| 24 | 41572739387791 |
| 25 | 144872448909191 |
| 26 | 504850696923520 |
| 27 | 1759300875378480 |