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 | 1 |
| 3 | 4 |
| 4 | 19 |
| 5 | 124 |
| 6 | 931 |
| 7 | 7801 |
| 8 | 68685 |
| 9 | 630850 |
| 10 | 5966610 |
| 11 | 57808920 |
| 12 | 571178751 |
| 13 | 5737672339 |
| 14 | 58455577800 |
| 15 | 602859484608 |
| 16 | 6283968796705 |
| 17 | 66119472527814 |
| 18 | 701526880303315 |
| 19 | 7498841163925819 |
| 20 | 80696081185766970 |
| 21 | 873654670250482120 |
| 22 | 9510760874015305314 |
| 23 | 104056578392127906720 |