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 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 31 |
| 5 | 178 |
| 6 | 1200 |
| 7 | 9588 |
| 8 | 86592 |
| 9 | 887086 |
| 10 | 10035164 |
| 11 | 125472246 |
| 12 | 1705102394 |
| 13 | 25175822644 |
| 14 | 399387494956 |
| 15 | 6801042408728 |
| 16 | 123348694663480 |
| 17 | 2379855020533664 |
| 18 | 48569042602254128 |
| 19 | 1047134236970183664 |
| 20 | 23748242269316806752 |
| 21 | 565834452464428045872 |
| 22 | 14117321495269290091440 |