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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 34 |
| 4 | 277 |
| 5 | 3402 |
| 6 | 36170 |
| 7 | 407463 |
| 8 | 4491564 |
| 9 | 49926988 |
| 10 | 553211363 |
| 11 | 6137270812 |
| 12 | 68054635036 |
| 13 | 754774491429 |
| 14 | 8370420537086 |
| 15 | 92830050637086 |
| 16 | 1029498223070793 |
| 17 | 11417322172518550 |
| 18 | 126619992693837974 |
| 19 | 1404237451180502875 |
| 20 | 15573231068749231000 |