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 | 3 |
| 2 | 12 |
| 3 | 51 |
| 4 | 204 |
| 5 | 819 |
| 6 | 3276 |
| 7 | 13107 |
| 8 | 52428 |
| 9 | 209715 |
| 10 | 838860 |
| 11 | 3355443 |
| 12 | 13421772 |
| 13 | 53687091 |
| 14 | 214748364 |
| 15 | 858993459 |
| 16 | 3435973836 |
| 17 | 13743895347 |
| 18 | 54975581388 |
| 19 | 219902325555 |
| 20 | 879609302220 |
| 21 | 3518437208883 |
| 22 | 14073748835532 |
| 23 | 56294995342131 |
| 24 | 225179981368524 |
| 25 | 900719925474099 |