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 | 4 |
| 3 | 8 |
| 4 | 17 |
| 5 | 38 |
| 6 | 90 |
| 7 | 224 |
| 8 | 585 |
| 9 | 1594 |
| 10 | 4520 |
| 11 | 13288 |
| 12 | 40409 |
| 13 | 126782 |
| 14 | 409646 |
| 15 | 1360512 |
| 16 | 4637681 |
| 17 | 16202034 |
| 18 | 57941164 |
| 19 | 211860488 |
| 20 | 791272129 |
| 21 | 3015807254 |
| 22 | 11719800674 |
| 23 | 46401584096 |
| 24 | 187039192185 |
| 25 | 767058993386 |
| 26 | 3198568491792 |
| 27 | 13553864902504 |