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 | 6 |
| 3 | 43 |
| 4 | 291 |
| 5 | 1992 |
| 6 | 13595 |
| 7 | 92845 |
| 8 | 633966 |
| 9 | 4329023 |
| 10 | 29560367 |
| 11 | 201850896 |
| 12 | 1378323999 |
| 13 | 9411785201 |
| 14 | 64267689006 |
| 15 | 438847231427 |
| 16 | 2996636337771 |
| 17 | 20462312853336 |
| 18 | 139725412120339 |
| 19 | 954104794142789 |
| 20 | 6515035056168654 |