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 | 4 |
| 2 | 24 |
| 3 | 184 |
| 4 | 1704 |
| 5 | 18424 |
| 6 | 227304 |
| 7 | 3147064 |
| 8 | 48278184 |
| 9 | 812387704 |
| 10 | 14872295784 |
| 11 | 294192418744 |
| 12 | 6251984167464 |
| 13 | 142032703137784 |
| 14 | 3434617880825064 |
| 15 | 88075274293319224 |
| 16 | 2387099326339205544 |
| 17 | 68177508876215724664 |
| 18 | 2046501717592969431144 |
| 19 | 64408432189100396344504 |