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 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 62 |
| 4 | 402 |
| 5 | 2662 |
| 6 | 17914 |
| 7 | 122040 |
| 8 | 839154 |
| 9 | 5811758 |
| 10 | 40482530 |
| 11 | 283311470 |
| 12 | 1990464450 |
| 13 | 14030571258 |
| 14 | 99179197512 |
| 15 | 702789627712 |
| 16 | 4990636603986 |
| 17 | 35506061422530 |
| 18 | 253030893941362 |
| 19 | 1805893735209486 |
| 20 | 12906043894108162 |
| 21 | 92346511605008562 |
| 22 | 661494201448139850 |