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 | 11 |
| 2 | 88 |
| 3 | 561 |
| 4 | 3124 |
| 5 | 15642 |
| 6 | 72303 |
| 7 | 312708 |
| 8 | 1280235 |
| 9 | 4999247 |
| 10 | 18739589 |
| 11 | 67751289 |
| 12 | 237202702 |
| 13 | 806779050 |
| 14 | 2673066187 |
| 15 | 8647158487 |
| 16 | 27365420159 |
| 17 | 84865235213 |
| 18 | 258285903491 |
| 19 | 772463952667 |
| 20 | 2272807540322 |
| 21 | 6585644471945 |