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 | 1 |
| 3 | 4 |
| 4 | 18 |
| 5 | 77 |
| 6 | 346 |
| 7 | 1578 |
| 8 | 7396 |
| 9 | 35297 |
| 10 | 171352 |
| 11 | 843067 |
| 12 | 4196502 |
| 13 | 21092793 |
| 14 | 106912874 |
| 15 | 545851964 |
| 16 | 2804641873 |
| 17 | 14491337393 |
| 18 | 75248330560 |
| 19 | 392476202012 |
| 20 | 2055245665857 |
| 21 | 10801441911431 |
| 22 | 56953955507744 |
| 23 | 301207374937558 |