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 | 1 |
| 2 | 9 |
| 3 | 109 |
| 4 | 1541 |
| 5 | 23823 |
| 6 | 390135 |
| 7 | 6651051 |
| 8 | 116798643 |
| 9 | 2098313686 |
| 10 | 38382509118 |
| 11 | 712447023590 |
| 12 | 13385500614902 |
| 13 | 254065657922154 |
| 14 | 4864482597112186 |
| 15 | 93840443376075810 |
| 16 | 1822169236520766546 |
| 17 | 35586928273002974487 |
| 18 | 698572561837366684479 |
| 19 | 13775697096997873764647 |