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 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 30 |
| 6 | 101 |
| 7 | 370 |
| 8 | 1459 |
| 9 | 6161 |
| 10 | 27741 |
| 11 | 132621 |
| 12 | 670444 |
| 13 | 3571013 |
| 14 | 19975956 |
| 15 | 117026702 |
| 16 | 716199026 |
| 17 | 4568532550 |
| 18 | 30313253547 |
| 19 | 208834580360 |
| 20 | 1491280419431 |
| 21 | 11021454603693 |
| 22 | 84184429969735 |
| 23 | 663707628683503 |