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 | 1 |
| 1 | 5 |
| 2 | 30 |
| 3 | 193 |
| 4 | 1286 |
| 5 | 8754 |
| 6 | 60460 |
| 7 | 421985 |
| 8 | 2968902 |
| 9 | 21019510 |
| 10 | 149572292 |
| 11 | 1068795930 |
| 12 | 7664092060 |
| 13 | 55121602436 |
| 14 | 397464604440 |
| 15 | 2872406652001 |
| 16 | 20799171328070 |
| 17 | 150869330458830 |
| 18 | 1096046132412628 |
| 19 | 7973709600124958 |
| 20 | 58081342410990516 |
| 21 | 423551998861478140 |