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 | 4 |
| 2 | 16 |
| 3 | 62 |
| 4 | 239 |
| 5 | 920 |
| 6 | 3540 |
| 7 | 13620 |
| 8 | 52401 |
| 9 | 201604 |
| 10 | 775636 |
| 11 | 2984122 |
| 12 | 11480879 |
| 13 | 44170640 |
| 14 | 169938680 |
| 15 | 653808840 |
| 16 | 2515413201 |
| 17 | 9677604804 |
| 18 | 37232862856 |
| 19 | 143246816182 |
| 20 | 551116641919 |
| 21 | 2120323237160 |
| 22 | 8157566453420 |
| 23 | 31384785713660 |
| 24 | 120747379738401 |