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 | 3 |
| 3 | 17 |
| 4 | 131 |
| 5 | 1055 |
| 6 | 8615 |
| 7 | 72951 |
| 8 | 633932 |
| 9 | 5602768 |
| 10 | 50193913 |
| 11 | 454577490 |
| 12 | 4153943134 |
| 13 | 38243708524 |
| 14 | 354330372215 |
| 15 | 3300752009165 |
| 16 | 30892997367352 |
| 17 | 290332329192655 |
| 18 | 2738477783884855 |
| 19 | 25913537508233527 |
| 20 | 245923809778144431 |
| 21 | 2339944887042508496 |
| 22 | 22316931815316988517 |