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 | 4 |
| 2 | 10 |
| 3 | 20 |
| 4 | 55 |
| 5 | 136 |
| 6 | 430 |
| 7 | 1300 |
| 8 | 4435 |
| 9 | 15084 |
| 10 | 53764 |
| 11 | 192700 |
| 12 | 704370 |
| 13 | 2589304 |
| 14 | 9608050 |
| 15 | 35824240 |
| 16 | 134301715 |
| 17 | 505421344 |
| 18 | 1909209550 |
| 19 | 7234153420 |
| 20 | 27489127708 |
| 21 | 104717491064 |
| 22 | 399827748310 |
| 23 | 1529763696820 |