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 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 14 |
| 5 | 70 |
| 6 | 372 |
| 7 | 2058 |
| 8 | 11752 |
| 9 | 68706 |
| 10 | 409130 |
| 11 | 2472646 |
| 12 | 15127620 |
| 13 | 93504944 |
| 14 | 583032968 |
| 15 | 3662883960 |
| 16 | 23163461280 |
| 17 | 147329432094 |
| 18 | 941880843108 |
| 19 | 6049001532148 |
| 20 | 39007700026460 |
| 21 | 252477751201074 |
| 22 | 1639657957610596 |
| 23 | 10680997864879592 |
| 24 | 69772819359471480 |
| 25 | 456959583009324200 |