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 | 1 |
| 2 | 6 |
| 3 | 30 |
| 4 | 143 |
| 5 | 671 |
| 6 | 3132 |
| 7 | 14601 |
| 8 | 68101 |
| 9 | 318035 |
| 10 | 1487661 |
| 11 | 6971222 |
| 12 | 32727472 |
| 13 | 153926409 |
| 14 | 725264305 |
| 15 | 3423262180 |
| 16 | 16185240446 |
| 17 | 76648901377 |
| 18 | 363557014067 |
| 19 | 1726994886004 |
| 20 | 8215502584008 |
| 21 | 39135887682617 |
| 22 | 186676023857041 |
| 23 | 891557875400175 |