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 | 4 |
| 3 | 19 |
| 4 | 72 |
| 5 | 355 |
| 6 | 1347 |
| 7 | 6843 |
| 8 | 26077 |
| 9 | 135752 |
| 10 | 519336 |
| 11 | 2760110 |
| 12 | 10591394 |
| 13 | 57299551 |
| 14 | 220393887 |
| 15 | 1210772453 |
| 16 | 4665698732 |
| 17 | 25974365600 |
| 18 | 100243916036 |
| 19 | 564517479641 |
| 20 | 2181476412875 |
| 21 | 12407767954139 |
| 22 | 48002072364351 |
| 23 | 275392803316254 |
| 24 | 1066512702720864 |
| 25 | 6164746100658825 |
| 26 | 23896975393255717 |