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) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 9 |
| 4 | 21 |
| 5 | 46 |
| 6 | 99 |
| 7 | 215 |
| 8 | 464 |
| 9 | 999 |
| 10 | 2154 |
| 11 | 4641 |
| 12 | 9999 |
| 13 | 21544 |
| 14 | 46415 |
| 15 | 99999 |
| 16 | 215443 |
| 17 | 464158 |
| 18 | 999999 |
| 19 | 2154434 |
| 20 | 4641588 |
| 21 | 9999999 |
| 22 | 21544346 |
| 23 | 46415888 |
| 24 | 99999999 |
| 25 | 215443469 |
| 26 | 464158883 |
| 27 | 999999999 |
| 28 | 2154434690 |
| 29 | 4641588833 |
| 30 | 9999999999 |