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 | 0 |
| 2 | 9 |
| 3 | 9 |
| 4 | 252 |
| 5 | 819 |
| 6 | 11754 |
| 7 | 72585 |
| 8 | 803448 |
| 9 | 6978159 |
| 10 | 73047510 |
| 11 | 744922341 |
| 12 | 8023947732 |
| 13 | 88219609227 |
| 14 | 993117723282 |
| 15 | 11397388906305 |
| 16 | 132852212160624 |
| 17 | 1568346473860839 |
| 18 | 18699577205645646 |
| 19 | 224600363892164061 |
| 20 | 2711096523623447820 |
| 21 | 32815659723020049411 |
| 22 | 397495008150096639114 |