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 | 18 |
| 3 | 96 |
| 4 | 575 |
| 5 | 3706 |
| 6 | 25078 |
| 7 | 175666 |
| 8 | 1262723 |
| 9 | 9261018 |
| 10 | 69024147 |
| 11 | 521281642 |
| 12 | 3980391050 |
| 13 | 30678331440 |
| 14 | 238350850248 |
| 15 | 1864751821958 |
| 16 | 14678131286357 |
| 17 | 116160233811868 |
| 18 | 923684828888152 |
| 19 | 7376541052964806 |
| 20 | 59137050311947284 |
| 21 | 475757909357776656 |
| 22 | 3839678158239147611 |