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 | 1 |
| 2 | 5 |
| 3 | 36 |
| 4 | 245 |
| 5 | 1681 |
| 6 | 11520 |
| 7 | 78961 |
| 8 | 541205 |
| 9 | 3709476 |
| 10 | 25425125 |
| 11 | 174266401 |
| 12 | 1194439680 |
| 13 | 8186811361 |
| 14 | 56113239845 |
| 15 | 384605867556 |
| 16 | 2636127833045 |
| 17 | 18068288963761 |
| 18 | 123841894913280 |
| 19 | 848824975429201 |
| 20 | 5817932933091125 |
| 21 | 39876705556208676 |
| 22 | 273319005960369605 |
| 23 | 1873356336166378561 |