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 | 10 |
| 3 | 76 |
| 4 | 540 |
| 5 | 3751 |
| 6 | 25840 |
| 7 | 177451 |
| 8 | 1217160 |
| 9 | 8344876 |
| 10 | 57202750 |
| 11 | 392089501 |
| 12 | 2687463360 |
| 13 | 18420257701 |
| 14 | 126254611990 |
| 15 | 865362736876 |
| 16 | 5931286406640 |
| 17 | 40653646980451 |
| 18 | 278644255208560 |
| 19 | 1909856172864751 |
| 20 | 13090349042248500 |