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 | 1 |
| 2 | 5 |
| 3 | 21 |
| 4 | 85 |
| 5 | 342 |
| 6 | 1380 |
| 7 | 5598 |
| 8 | 22836 |
| 9 | 93640 |
| 10 | 385734 |
| 11 | 1595232 |
| 12 | 6619374 |
| 13 | 27545269 |
| 14 | 114901685 |
| 15 | 480282369 |
| 16 | 2011058681 |
| 17 | 8433331523 |
| 18 | 35410037683 |
| 19 | 148842787215 |
| 20 | 626234799703 |
| 21 | 2636930617597 |
| 22 | 11111302351505 |
| 23 | 46848507630321 |
| 24 | 197631791675365 |