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 | 1 |
| 2 | 9 |
| 3 | 55 |
| 4 | 441 |
| 5 | 4316 |
| 6 | 46867 |
| 7 | 566714 |
| 8 | 7550601 |
| 9 | 109118728 |
| 10 | 1696640501 |
| 11 | 28209128344 |
| 12 | 498557098921 |
| 13 | 9320449092072 |
| 14 | 183575505529431 |
| 15 | 3796015849264216 |
| 16 | 82156098504947473 |
| 17 | 1856012774517648896 |
| 18 | 43663382492497648777 |
| 19 | 1067393396478808265656 |
| 20 | 27062739020373087036281 |
| 21 | 710410408414549934445376 |
| 22 | 19277762831507022675509139 |