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 | 6 |
| 2 | 51 |
| 3 | 456 |
| 4 | 4191 |
| 5 | 39174 |
| 6 | 370329 |
| 7 | 3529284 |
| 8 | 33838854 |
| 9 | 325978044 |
| 10 | 3152058630 |
| 11 | 30572797920 |
| 12 | 297294956070 |
| 13 | 2897207397420 |
| 14 | 28286321963370 |
| 15 | 276611636831640 |
| 16 | 2708781551458665 |
| 17 | 26559205696513590 |
| 18 | 260695647288540915 |
| 19 | 2561413004129212440 |
| 20 | 25188928968792165495 |