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 | 24 |
| 3 | 111 |
| 4 | 500 |
| 5 | 2210 |
| 6 | 9632 |
| 7 | 41531 |
| 8 | 177564 |
| 9 | 754014 |
| 10 | 3184016 |
| 11 | 13382710 |
| 12 | 56026984 |
| 13 | 233765636 |
| 14 | 972504704 |
| 15 | 4035441491 |
| 16 | 16707488684 |
| 17 | 69033916166 |
| 18 | 284733161264 |
| 19 | 1172510645666 |
| 20 | 4821324991064 |
| 21 | 19799091571676 |
| 22 | 81208982686784 |
| 23 | 332726301861086 |
| 24 | 1361862906980120 |