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 | 19 |
| 2 | 228 |
| 3 | 2109 |
| 4 | 16454 |
| 5 | 113164 |
| 6 | 705527 |
| 7 | 4060870 |
| 8 | 21863490 |
| 9 | 111178196 |
| 10 | 537978635 |
| 11 | 2491812228 |
| 12 | 11100464810 |
| 13 | 47746888432 |
| 14 | 198952868210 |
| 15 | 805306011651 |
| 16 | 3174012174213 |
| 17 | 12206318615473 |
| 18 | 45884592463642 |