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 | 5 |
| 3 | 33 |
| 4 | 261 |
| 5 | 2361 |
| 6 | 23805 |
| 7 | 263313 |
| 8 | 3161781 |
| 9 | 40907241 |
| 10 | 567074925 |
| 11 | 8385483393 |
| 12 | 131787520101 |
| 13 | 2194406578521 |
| 14 | 38605941817245 |
| 15 | 715814473193073 |
| 16 | 13956039627763221 |
| 17 | 285509132504621001 |
| 18 | 6116719419966460365 |