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 | 8 |
| 4 | 38 |
| 5 | 275 |
| 6 | 2614 |
| 7 | 30346 |
| 8 | 415360 |
| 9 | 6513999 |
| 10 | 115063118 |
| 11 | 2259975228 |
| 12 | 48860184539 |
| 13 | 1153140907207 |
| 14 | 29502289676802 |
| 15 | 813371784160602 |
| 16 | 24040797257734161 |
| 17 | 758379326971459945 |
| 18 | 25432414455826532993 |
| 19 | 903508909333199982128 |
| 20 | 33897272145242834426910 |
| 21 | 1339265974992611047296679 |