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 | 21 |
| 1 | 221 |
| 2 | 621 |
| 3 | 1221 |
| 4 | 2021 |
| 5 | 3021 |
| 6 | 4221 |
| 7 | 5621 |
| 8 | 7221 |
| 9 | 9021 |
| 10 | 11021 |
| 11 | 13221 |
| 12 | 15621 |
| 13 | 18221 |
| 14 | 21021 |
| 15 | 24021 |
| 16 | 27221 |
| 17 | 30621 |
| 18 | 34221 |
| 19 | 38021 |
| 20 | 42021 |
| 21 | 46221 |
| 22 | 50621 |
| 23 | 55221 |
| 24 | 60021 |
| 25 | 65021 |
| 26 | 70221 |
| 27 | 75621 |
| 28 | 81221 |
| 29 | 87021 |
| 30 | 93021 |
| 31 | 99221 |
| 32 | 105621 |
| 33 | 112221 |
| 34 | 119021 |
| 35 | 126021 |
| 36 | 133221 |
| 37 | 140621 |
| 38 | 148221 |