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 | 2 |
| 1 | 2 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 32 |
| 6 | 122 |
| 7 | 544 |
| 8 | 2770 |
| 9 | 15872 |
| 10 | 101042 |
| 11 | 707584 |
| 12 | 5405530 |
| 13 | 44736512 |
| 14 | 398721962 |
| 15 | 3807514624 |
| 16 | 38783024290 |
| 17 | 419730685952 |
| 18 | 4809759350882 |
| 19 | 58177770225664 |
| 20 | 740742376475050 |
| 21 | 9902996106248192 |
| 22 | 138697748786275802 |
| 23 | 2030847773013704704 |
| 24 | 31029068327114173810 |
| 25 | 493842960380415967232 |