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 | 15 |
| 2 | 115 |
| 3 | 735 |
| 4 | 5435 |
| 5 | 40965 |
| 6 | 315991 |
| 7 | 2469909 |
| 8 | 19495747 |
| 9 | 154956453 |
| 10 | 1237813755 |
| 11 | 9923510469 |
| 12 | 79762415747 |
| 13 | 642295225197 |
| 14 | 5178982417003 |
| 15 | 41798669030805 |
| 16 | 337575342572995 |
| 17 | 2727627544083901 |
| 18 | 22046802610388635 |
| 19 | 178241899736229829 |