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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 5 |
| 5 | 24 |
| 6 | 128 |
| 7 | 835 |
| 8 | 6423 |
| 9 | 56410 |
| 10 | 554306 |
| 11 | 6016077 |
| 12 | 71426225 |
| 13 | 920484892 |
| 14 | 12793635300 |
| 15 | 190730117959 |
| 16 | 3035659077083 |
| 17 | 51371100102990 |
| 18 | 920989078354838 |
| 19 | 17437084517068465 |
| 20 | 347647092476801301 |
| 21 | 7280060180210901232 |
| 22 | 159755491837445900120 |
| 23 | 3665942433747225901707 |