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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 19 |
| 5 | 257 |
| 6 | 3167 |
| 7 | 38909 |
| 8 | 498235 |
| 9 | 6811453 |
| 10 | 100623211 |
| 11 | 1612937661 |
| 12 | 28033056683 |
| 13 | 526501880989 |
| 14 | 10639153638795 |
| 15 | 230269650097469 |
| 16 | 5315570416909995 |
| 17 | 130370239796988957 |
| 18 | 3385531348514480651 |
| 19 | 92801566389186549245 |
| 20 | 2677687663571344712043 |
| 21 | 81124824154544921317597 |